BASELINE: Update Chromium to 74.0.3729.159

Change-Id: I8d2497da544c275415aedd94dd25328d555de811
Reviewed-by: Michael Brüning <michael.bruning@qt.io>

30 files changed, 344 insertions, 434 deletions

diff --git a/chromium/components/variations/BUILD.gn b/chromium/components/variations/BUILD.gn
index c764b7d13ea..5caa15ce040 100644
--- a/chromium/components/variations/BUILD.gn
+++ b/chromium/components/variations/BUILD.gn
@@ -21,8 +21,6 @@ static_library("variations") {
     "client_filterable_state.h",
     "entropy_provider.cc",
     "entropy_provider.h",
-    "experiment_labels.cc",
-    "experiment_labels.h",
     "hashing.cc",
     "hashing.h",
     "metrics.cc",
@@ -49,8 +47,6 @@ static_library("variations") {
     "variations_associated_data.h",
     "variations_crash_keys.cc",
     "variations_crash_keys.h",
-    "variations_experiment_util.cc",
-    "variations_experiment_util.h",
     "variations_http_header_provider.cc",
     "variations_http_header_provider.h",
     "variations_id_collection.cc",
@@ -103,12 +99,16 @@ if (is_android) {
   }
 
   android_library("load_seed_result_enum_java") {
-    deps = [ "//base:base_java" ]
+    deps = [
+      "//base:base_java",
+    ]
     srcjar_deps = [ ":load_seed_result_enum_srcjar" ]
   }
 
   java_cpp_enum("load_seed_result_enum_srcjar") {
-    sources = [ "metrics.h" ]
+    sources = [
+      "metrics.h",
+    ]
   }
 }
 
@@ -135,7 +135,6 @@ source_set("unit_tests") {
     "active_field_trials_unittest.cc",
     "child_process_field_trial_syncer_unittest.cc",
     "entropy_provider_unittest.cc",
-    "experiment_labels_unittest.cc",
     "hashing_unittest.cc",
     "net/variations_command_line_unittest.cc",
     "net/variations_http_headers_unittest.cc",
diff --git a/chromium/components/variations/android/java/src/org/chromium/components/variations/firstrun/VariationsSeedFetcher.java b/chromium/components/variations/android/java/src/org/chromium/components/variations/firstrun/VariationsSeedFetcher.java
index 08081611f02..01054b79c19 100644
--- a/chromium/components/variations/android/java/src/org/chromium/components/variations/firstrun/VariationsSeedFetcher.java
+++ b/chromium/components/variations/android/java/src/org/chromium/components/variations/firstrun/VariationsSeedFetcher.java
@@ -6,6 +6,7 @@ package org.chromium.components.variations.firstrun;
 
 import android.content.SharedPreferences;
 import android.os.SystemClock;
+import android.support.annotation.IntDef;
 
 import org.chromium.base.ContextUtils;
 import org.chromium.base.Log;
@@ -17,6 +18,8 @@ import org.chromium.base.metrics.CachedMetrics.TimesHistogramSample;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
 import java.net.HttpURLConnection;
 import java.net.MalformedURLException;
 import java.net.SocketTimeoutException;
@@ -27,7 +30,6 @@ import java.text.SimpleDateFormat;
 import java.util.Arrays;
 import java.util.Date;
 import java.util.Locale;
-import java.util.concurrent.TimeUnit;
 
 /**
  * Fetches the variations seed before the actual first run of Chrome.
@@ -35,7 +37,12 @@ import java.util.concurrent.TimeUnit;
 public class VariationsSeedFetcher {
     private static final String TAG = "VariationsSeedFetch";
 
-    public enum VariationsPlatform { ANDROID, ANDROID_WEBVIEW }
+    @IntDef({VariationsPlatform.ANDROID, VariationsPlatform.ANDROID_WEBVIEW})
+    @Retention(RetentionPolicy.SOURCE)
+    public @interface VariationsPlatform {
+        int ANDROID = 0;
+        int ANDROID_WEBVIEW = 1;
+    }
 
     private static final String VARIATIONS_SERVER_URL =
             "https://clientservices.googleapis.com/chrome-variations/seed?osname=";
@@ -85,7 +92,7 @@ public class VariationsSeedFetcher {
 
     @VisibleForTesting
     protected HttpURLConnection getServerConnection(
-            VariationsPlatform platform, String restrictMode, String milestone, String channel)
+            @VariationsPlatform int platform, String restrictMode, String milestone, String channel)
             throws MalformedURLException, IOException {
         String urlString = getConnectionString(platform, restrictMode, milestone, channel);
         URL url = new URL(urlString);
@@ -93,14 +100,14 @@ public class VariationsSeedFetcher {
     }
 
     @VisibleForTesting
-    protected String getConnectionString(
-            VariationsPlatform platform, String restrictMode, String milestone, String channel) {
+    protected String getConnectionString(@VariationsPlatform int platform, String restrictMode,
+            String milestone, String channel) {
         String urlString = VARIATIONS_SERVER_URL;
         switch (platform) {
-            case ANDROID:
+            case VariationsPlatform.ANDROID:
                 urlString += "android";
                 break;
-            case ANDROID_WEBVIEW:
+            case VariationsPlatform.ANDROID_WEBVIEW:
                 urlString += "android_webview";
                 break;
             default:
@@ -192,14 +199,14 @@ public class VariationsSeedFetcher {
 
     private void recordSeedFetchTime(long timeDeltaMillis) {
         Log.i(TAG, "Fetched first run seed in " + timeDeltaMillis + " ms");
-        TimesHistogramSample histogram = new TimesHistogramSample(
-                "Variations.FirstRun.SeedFetchTime", TimeUnit.MILLISECONDS);
+        TimesHistogramSample histogram =
+                new TimesHistogramSample("Variations.FirstRun.SeedFetchTime");
         histogram.record(timeDeltaMillis);
     }
 
     private void recordSeedConnectTime(long timeDeltaMillis) {
-        TimesHistogramSample histogram = new TimesHistogramSample(
-                "Variations.FirstRun.SeedConnectTime", TimeUnit.MILLISECONDS);
+        TimesHistogramSample histogram =
+                new TimesHistogramSample("Variations.FirstRun.SeedConnectTime");
         histogram.record(timeDeltaMillis);
     }
 
@@ -217,7 +224,7 @@ public class VariationsSeedFetcher {
      * connection.
      */
     public SeedInfo downloadContent(
-            VariationsPlatform platform, String restrictMode, String milestone, String channel)
+            @VariationsPlatform int platform, String restrictMode, String milestone, String channel)
             throws SocketTimeoutException, UnknownHostException, IOException {
         HttpURLConnection connection = null;
         try {
diff --git a/chromium/components/variations/entropy_provider.cc b/chromium/components/variations/entropy_provider.cc
index 0c46368228a..d7eb868650f 100644
--- a/chromium/components/variations/entropy_provider.cc
+++ b/chromium/components/variations/entropy_provider.cc
@@ -37,8 +37,9 @@ double SHA1EntropyProvider::GetEntropyForTrial(
   // distribution given the same |trial_name|. When using such a low entropy
   // source, NormalizedMurmurHashEntropyProvider should be used instead.
   std::string input(entropy_source_);
-  input.append(randomization_seed == 0 ? trial_name : base::UintToString(
-                                                          randomization_seed));
+  input.append(randomization_seed == 0
+                   ? trial_name
+                   : base::NumberToString(randomization_seed));
 
   unsigned char sha1_hash[base::kSHA1Length];
   base::SHA1HashBytes(reinterpret_cast<const unsigned char*>(input.c_str()),
diff --git a/chromium/components/variations/entropy_provider_unittest.cc b/chromium/components/variations/entropy_provider_unittest.cc
index de2ca1027db..79040f40cf3 100644
--- a/chromium/components/variations/entropy_provider_unittest.cc
+++ b/chromium/components/variations/entropy_provider_unittest.cc
@@ -91,7 +91,7 @@ class SHA1EntropyGenerator : public TrialEntropyGenerator {
     const int low_entropy_source =
         static_cast<uint16_t>(base::RandInt(0, kMaxLowEntropySize - 1));
     const std::string high_entropy_source =
-        base::GenerateGUID() + base::IntToString(low_entropy_source);
+        base::GenerateGUID() + base::NumberToString(low_entropy_source);
     return GenerateSHA1Entropy(high_entropy_source, trial_name_);
   }
 
diff --git a/chromium/components/variations/experiment_labels.cc b/chromium/components/variations/experiment_labels.cc
deleted file mode 100644
index 1b0d85a5c96..00000000000
--- a/chromium/components/variations/experiment_labels.cc
+++ /dev/null
@@ -1,49 +0,0 @@
-// Copyright 2014 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "components/variations/experiment_labels.h"
-
-#include <vector>
-
-#include "base/logging.h"
-#include "base/strings/string_number_conversions.h"
-#include "base/strings/string_split.h"
-#include "base/strings/string_util.h"
-#include "base/strings/utf_string_conversions.h"
-#include "components/variations/variations_associated_data.h"
-#include "components/variations/variations_experiment_util.h"
-
-namespace variations {
-namespace {
-
-const char kVariationPrefix[] = "CrVar";
-
-}  // namespace
-
-base::string16 ExtractNonVariationLabels(const base::string16& labels) {
-  // First, split everything by the label separator.
-  std::vector<base::StringPiece16> entries = base::SplitStringPiece(
-      labels, base::StringPiece16(&kExperimentLabelSeparator, 1),
-      base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL);
-
-  // For each label, keep the ones that do not look like a Variations label.
-  base::string16 non_variation_labels;
-  for (const base::StringPiece16& entry : entries) {
-    if (entry.empty() ||
-        base::StartsWith(entry,
-                         base::ASCIIToUTF16(kVariationPrefix),
-                         base::CompareCase::INSENSITIVE_ASCII)) {
-      continue;
-    }
-
-    // Dump the whole thing, including the timestamp.
-    if (!non_variation_labels.empty())
-      non_variation_labels += kExperimentLabelSeparator;
-    entry.AppendToString(&non_variation_labels);
-  }
-
-  return non_variation_labels;
-}
-
-}  // namespace variations
diff --git a/chromium/components/variations/experiment_labels.h b/chromium/components/variations/experiment_labels.h
deleted file mode 100644
index cd10825aa57..00000000000
--- a/chromium/components/variations/experiment_labels.h
+++ /dev/null
@@ -1,20 +0,0 @@
-// Copyright 2014 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef COMPONENTS_VARIATIONS_EXPERIMENT_LABELS_H_
-#define COMPONENTS_VARIATIONS_EXPERIMENT_LABELS_H_
-
-#include "base/metrics/field_trial.h"
-#include "base/strings/string16.h"
-
-namespace variations {
-
-// Takes the value of experiment_labels from the registry and returns a valid
-// experiment_labels string value containing only the labels that are not
-// associated with Chrome Variations.
-base::string16 ExtractNonVariationLabels(const base::string16& labels);
-
-}  // namespace variations
-
-#endif  // COMPONENTS_VARIATIONS_EXPERIMENT_LABELS_H_
diff --git a/chromium/components/variations/experiment_labels_unittest.cc b/chromium/components/variations/experiment_labels_unittest.cc
deleted file mode 100644
index 797f57a82f8..00000000000
--- a/chromium/components/variations/experiment_labels_unittest.cc
+++ /dev/null
@@ -1,87 +0,0 @@
-// Copyright 2014 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "components/variations/experiment_labels.h"
-
-#include <stddef.h>
-
-#include <set>
-#include <string>
-#include <vector>
-
-#include "base/macros.h"
-#include "base/metrics/field_trial.h"
-#include "base/stl_util.h"
-#include "base/strings/string_split.h"
-#include "base/strings/utf_string_conversions.h"
-#include "components/variations/variations_associated_data.h"
-#include "testing/gtest/include/gtest/gtest.h"
-
-namespace variations {
-
-TEST(ExperimentLabelsTest, ExtractNonVariationLabels) {
-  struct {
-    const char* input_label;
-    const char* expected_output;
-  } test_cases[] = {
-      // Empty
-      {"", ""},
-      // One
-      {"gcapi_brand=123|Tue, 21 Jan 2014 15:30:21 GMT",
-       "gcapi_brand=123|Tue, 21 Jan 2014 15:30:21 GMT"},
-      // Three
-      {"CrVar1=123|Tue, 21 Jan 2014 15:30:21 GMT;"
-       "experiment1=456|Tue, 21 Jan 2014 15:30:21 GMT;"
-       "experiment2=789|Tue, 21 Jan 2014 15:30:21 GMT;"
-       "CrVar1=123|Tue, 21 Jan 2014 15:30:21 GMT",
-       "experiment1=456|Tue, 21 Jan 2014 15:30:21 GMT;"
-       "experiment2=789|Tue, 21 Jan 2014 15:30:21 GMT"},
-      // One and one Variation
-      {"gcapi_brand=123|Tue, 21 Jan 2014 15:30:21 GMT;"
-       "CrVar1=3310002|Tue, 21 Jan 2014 15:30:21 GMT",
-       "gcapi_brand=123|Tue, 21 Jan 2014 15:30:21 GMT"},
-      // One and one Variation, flipped
-      {"CrVar1=3310002|Tue, 21 Jan 2014 15:30:21 GMT;"
-       "gcapi_brand=123|Tue, 21 Jan 2014 15:30:21 GMT",
-       "gcapi_brand=123|Tue, 21 Jan 2014 15:30:21 GMT"},
-      // Sandwiched
-      {"CrVar1=3310002|Tue, 21 Jan 2014 15:30:21 GMT;"
-       "gcapi_brand=123|Tue, 21 Jan 2014 15:30:21 GMT;"
-       "CrVar2=3310003|Tue, 21 Jan 2014 15:30:21 GMT;"
-       "CrVar3=3310004|Tue, 21 Jan 2014 15:30:21 GMT",
-       "gcapi_brand=123|Tue, 21 Jan 2014 15:30:21 GMT"},
-      // Only Variations
-      {"CrVar1=3310002|Tue, 21 Jan 2014 15:30:21 GMT;"
-       "CrVar2=3310003|Tue, 21 Jan 2014 15:30:21 GMT;"
-       "CrVar3=3310004|Tue, 21 Jan 2014 15:30:21 GMT",
-       ""},
-      // Empty values
-      {"gcapi_brand=123|Tue, 21 Jan 2014 15:30:21 GMT;"
-       "CrVar1=3310002|Tue, 21 Jan 2014 15:30:21 GMT",
-       "gcapi_brand=123|Tue, 21 Jan 2014 15:30:21 GMT"},
-      // Trailing semicolon
-      {"gcapi_brand=123|Tue, 21 Jan 2014 15:30:21 GMT;"
-       "CrVar1=3310002|Tue, 21 Jan 2014 15:30:21 GMT;",  // Note the semi here.
-       "gcapi_brand=123|Tue, 21 Jan 2014 15:30:21 GMT"},
-      // Semis
-      {";;;;", ""},
-      // Three non-Variation labels
-      // Testing that the order is preserved.
-      {"experiment1=456|Tue, 21 Jan 2014 15:30:21 GMT;"
-       "experiment2=789|Tue, 21 Jan 2014 15:30:21 GMT;"
-       "experiment3=123|Tue, 21 Jan 2014 15:30:21 GMT",
-       "experiment1=456|Tue, 21 Jan 2014 15:30:21 GMT;"
-       "experiment2=789|Tue, 21 Jan 2014 15:30:21 GMT;"
-       "experiment3=123|Tue, 21 Jan 2014 15:30:21 GMT"},
-  };
-
-  for (size_t i = 0; i < base::size(test_cases); ++i) {
-    std::string non_variation_labels = base::UTF16ToUTF8(
-        ExtractNonVariationLabels(
-            base::ASCIIToUTF16(test_cases[i].input_label)));
-    EXPECT_EQ(test_cases[i].expected_output, non_variation_labels);
-  }
-}
-
-}  // namespace variations
diff --git a/chromium/components/variations/net/variations_http_headers.cc b/chromium/components/variations/net/variations_http_headers.cc
index 1b2eb27c137..c06fd473f75 100644
--- a/chromium/components/variations/net/variations_http_headers.cc
+++ b/chromium/components/variations/net/variations_http_headers.cc
@@ -6,8 +6,10 @@
 
 #include <stddef.h>
 
+#include <utility>
 #include <vector>
 
+#include "base/bind.h"
 #include "base/macros.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/stl_util.h"
@@ -27,25 +29,9 @@ namespace variations {
 
 namespace {
 
-const char* kSuffixesToSetHeadersFor[] = {
-    ".android.com",
-    ".doubleclick.com",
-    ".doubleclick.net",
-    ".ggpht.com",
-    ".googleadservices.com",
-    ".googleapis.com",
-    ".googlesyndication.com",
-    ".googleusercontent.com",
-    ".googlevideo.com",
-    ".gstatic.com",
-    ".litepages.googlezip.net",
-    ".ytimg.com",
-};
-
-// Exact hostnames in lowercase to set headers for.
-const char* kHostsToSetHeadersFor[] = {
-    "googleweblight.com",
-};
+// The name string for the header for variations information.
+// Note that prior to M33 this header was named X-Chrome-Variations.
+const char kClientDataHeader[] = "X-Client-Data";
 
 // The result of checking if a URL should have variations headers appended.
 // This enum is used to record UMA histogram values, and should not be
@@ -60,142 +46,194 @@ enum URLValidationResult {
   URL_VALIDATION_RESULT_SIZE,
 };
 
-// Checks whether headers should be appended to the |url|, based on the domain
-// of |url|. |url| is assumed to be valid, and to have an http/https scheme.
-bool IsGoogleDomain(const GURL& url) {
-  if (google_util::IsGoogleDomainUrl(url, google_util::ALLOW_SUBDOMAIN,
-                                     google_util::ALLOW_NON_STANDARD_PORTS)) {
-    return true;
+void LogUrlValidationHistogram(URLValidationResult result) {
+  UMA_HISTOGRAM_ENUMERATION("Variations.Headers.URLValidationResult", result,
+                            URL_VALIDATION_RESULT_SIZE);
+}
+
+bool ShouldAppendVariationsHeader(const GURL& url) {
+  if (!url.is_valid()) {
+    LogUrlValidationHistogram(INVALID_URL);
+    return false;
   }
-  if (google_util::IsYoutubeDomainUrl(url, google_util::ALLOW_SUBDOMAIN,
-                                      google_util::ALLOW_NON_STANDARD_PORTS)) {
-    return true;
+  if (!url.SchemeIsHTTPOrHTTPS()) {
+    LogUrlValidationHistogram(NEITHER_HTTP_HTTPS);
+    return false;
   }
+  if (!google_util::IsGoogleAssociatedDomainUrl(url)) {
+    LogUrlValidationHistogram(NOT_GOOGLE_DOMAIN);
+    return false;
+  }
+  // We check https here, rather than before the IsGoogleDomain() check, to know
+  // how many Google domains are being rejected by the change to https only.
+  if (!url.SchemeIs(url::kHttpsScheme)) {
+    LogUrlValidationHistogram(IS_GOOGLE_NOT_HTTPS);
+    return false;
+  }
+  LogUrlValidationHistogram(SHOULD_APPEND);
+  return true;
+}
+
+constexpr network::ResourceRequest* null_resource_request = nullptr;
+constexpr net::URLRequest* null_url_request = nullptr;
 
-  // Some domains don't have international TLD extensions, so testing for them
-  // is very straight forward.
-  const std::string host = url.host();
-  for (size_t i = 0; i < base::size(kSuffixesToSetHeadersFor); ++i) {
-    if (base::EndsWith(host, kSuffixesToSetHeadersFor[i],
-                       base::CompareCase::INSENSITIVE_ASCII))
-      return true;
+class VariationsHeaderHelper {
+ public:
+  // Note: It's OK to pass SignedIn::kNo if it's unknown, as it does not affect
+  // transmission of experiments coming from the variations server.
+  VariationsHeaderHelper(network::ResourceRequest* request,
+                         SignedIn signed_in = SignedIn::kNo)
+      : VariationsHeaderHelper(request,
+                               null_url_request,
+                               CreateVariationsHeader(signed_in)) {}
+  VariationsHeaderHelper(net::URLRequest* request,
+                         SignedIn signed_in = SignedIn::kNo)
+      : VariationsHeaderHelper(null_resource_request,
+                               request,
+                               CreateVariationsHeader(signed_in)) {}
+  VariationsHeaderHelper(network::ResourceRequest* request,
+                         const std::string& variations_header)
+      : VariationsHeaderHelper(request, null_url_request, variations_header) {}
+
+  bool AppendHeaderIfNeeded(const GURL& url, InIncognito incognito) {
+    // Note the criteria for attaching client experiment headers:
+    // 1. We only transmit to Google owned domains which can evaluate
+    // experiments.
+    //    1a. These include hosts which have a standard postfix such as:
+    //         *.doubleclick.net or *.googlesyndication.com or
+    //         exactly www.googleadservices.com or
+    //         international TLD domains *.google.<TLD> or *.youtube.<TLD>.
+    // 2. Only transmit for non-Incognito profiles.
+    // 3. For the X-Client-Data header, only include non-empty variation IDs.
+    if ((incognito == InIncognito::kYes) || !ShouldAppendVariationsHeader(url))
+      return false;
+
+    if (variations_header_.empty())
+      return false;
+
+    if (resource_request_) {
+      // Set the variations header to client_data_header rather than headers to
+      // be exempted from CORS checks.
+      resource_request_->client_data_header = variations_header_;
+    } else if (url_request_) {
+      url_request_->SetExtraRequestHeaderByName(kClientDataHeader,
+                                                variations_header_, false);
+    } else {
+      NOTREACHED();
+      return false;
+    }
+    return true;
   }
-  for (size_t i = 0; i < base::size(kHostsToSetHeadersFor); ++i) {
-    if (base::LowerCaseEqualsASCII(host, kHostsToSetHeadersFor[i]))
-      return true;
+
+ private:
+  static std::string CreateVariationsHeader(SignedIn signed_in) {
+    return VariationsHttpHeaderProvider::GetInstance()->GetClientDataHeader(
+        signed_in == SignedIn::kYes);
   }
 
-  return false;
-}
+  VariationsHeaderHelper(network::ResourceRequest* resource_request,
+                         net::URLRequest* url_request,
+                         std::string variations_header)
+      : resource_request_(resource_request), url_request_(url_request) {
+    DCHECK(resource_request_ || url_request_);
+    variations_header_ = std::move(variations_header);
+  }
 
-void LogUrlValidationHistogram(URLValidationResult result) {
-  UMA_HISTOGRAM_ENUMERATION("Variations.Headers.URLValidationResult", result,
-                            URL_VALIDATION_RESULT_SIZE);
-}
+  network::ResourceRequest* resource_request_;
+  net::URLRequest* url_request_;
+  std::string variations_header_;
 
-// Removes variations headers for requests when a redirect to a non-Google URL
-// occurs. This function is used as the callback parameter for
-// SimpleURLLoader::SetOnRedirectCallback() when
-// CreateSimpleURLLoaderWithVariationsHeaders() creates a SimpleURLLoader
-// object.
-void RemoveVariationsHeader(const net::RedirectInfo& redirect_info,
-                            const network::ResourceResponseHead& response_head,
-                            std::vector<std::string>* to_be_removed_headers) {
-  if (!ShouldAppendVariationHeaders(redirect_info.new_url))
-    to_be_removed_headers->push_back(kClientDataHeader);
-}
+  DISALLOW_COPY_AND_ASSIGN(VariationsHeaderHelper);
+};
 
 }  // namespace
 
-const char kClientDataHeader[] = "X-Client-Data";
+bool AppendVariationsHeader(const GURL& url,
+                            InIncognito incognito,
+                            SignedIn signed_in,
+                            network::ResourceRequest* request) {
+  return VariationsHeaderHelper(request, signed_in)
+      .AppendHeaderIfNeeded(url, incognito);
+}
 
-bool AppendVariationHeaders(const GURL& url,
+bool AppendVariationsHeader(const GURL& url,
                             InIncognito incognito,
                             SignedIn signed_in,
-                            net::HttpRequestHeaders* headers) {
-  // Note the criteria for attaching client experiment headers:
-  // 1. We only transmit to Google owned domains which can evaluate experiments.
-  //    1a. These include hosts which have a standard postfix such as:
-  //         *.doubleclick.net or *.googlesyndication.com or
-  //         exactly www.googleadservices.com or
-  //         international TLD domains *.google.<TLD> or *.youtube.<TLD>.
-  // 2. Only transmit for non-Incognito profiles.
-  // 3. For the X-Client-Data header, only include non-empty variation IDs.
-  if ((incognito == InIncognito::kYes) || !ShouldAppendVariationHeaders(url))
-    return false;
+                            net::URLRequest* request) {
+  return VariationsHeaderHelper(request, signed_in)
+      .AppendHeaderIfNeeded(url, incognito);
+}
 
-  const std::string variation_ids_header =
-      VariationsHttpHeaderProvider::GetInstance()->GetClientDataHeader(
-          signed_in == SignedIn::kYes);
-  if (!variation_ids_header.empty()) {
-    // Note that prior to M33 this header was named X-Chrome-Variations.
-    headers->SetHeaderIfMissing(kClientDataHeader, variation_ids_header);
-    return true;
-  }
-  return false;
+bool AppendVariationsHeaderWithCustomValue(const GURL& url,
+                                           InIncognito incognito,
+                                           const std::string& variations_header,
+                                           network::ResourceRequest* request) {
+  return VariationsHeaderHelper(request, variations_header)
+      .AppendHeaderIfNeeded(url, incognito);
 }
 
-bool AppendVariationHeadersUnknownSignedIn(const GURL& url,
+bool AppendVariationsHeaderUnknownSignedIn(const GURL& url,
                                            InIncognito incognito,
-                                           net::HttpRequestHeaders* headers) {
-  // Note: It's OK to pass SignedIn::kNo if it's unknown, as it does not affect
-  // transmission of experiments coming from the variations server.
-  return AppendVariationHeaders(url, incognito, SignedIn::kNo, headers);
+                                           network::ResourceRequest* request) {
+  return VariationsHeaderHelper(request).AppendHeaderIfNeeded(url, incognito);
+}
+
+bool AppendVariationsHeaderUnknownSignedIn(const GURL& url,
+                                           InIncognito incognito,
+                                           net::URLRequest* request) {
+  return VariationsHeaderHelper(request).AppendHeaderIfNeeded(url, incognito);
 }
 
-void StripVariationHeaderIfNeeded(const GURL& new_location,
-                                  net::URLRequest* request) {
-  if (!ShouldAppendVariationHeaders(new_location))
+void RemoveVariationsHeaderIfNeeded(
+    const net::RedirectInfo& redirect_info,
+    const network::ResourceResponseHead& response_head,
+    std::vector<std::string>* to_be_removed_headers) {
+  if (!ShouldAppendVariationsHeader(redirect_info.new_url))
+    to_be_removed_headers->push_back(kClientDataHeader);
+}
+
+void StripVariationsHeaderIfNeeded(const GURL& new_location,
+                                   net::URLRequest* request) {
+  if (!ShouldAppendVariationsHeader(new_location))
     request->RemoveRequestHeaderByName(kClientDataHeader);
 }
 
 std::unique_ptr<network::SimpleURLLoader>
-CreateSimpleURLLoaderWithVariationsHeaders(
+CreateSimpleURLLoaderWithVariationsHeader(
     std::unique_ptr<network::ResourceRequest> request,
     InIncognito incognito,
     SignedIn signed_in,
     const net::NetworkTrafficAnnotationTag& annotation_tag) {
-  bool variation_headers_added = AppendVariationHeaders(
-      request->url, incognito, signed_in, &request->headers);
+  bool variation_headers_added =
+      AppendVariationsHeader(request->url, incognito, signed_in, request.get());
   std::unique_ptr<network::SimpleURLLoader> simple_url_loader =
       network::SimpleURLLoader::Create(std::move(request), annotation_tag);
   if (variation_headers_added) {
     simple_url_loader->SetOnRedirectCallback(
-        base::BindRepeating(&RemoveVariationsHeader));
+        base::BindRepeating(&RemoveVariationsHeaderIfNeeded));
   }
   return simple_url_loader;
 }
 
 std::unique_ptr<network::SimpleURLLoader>
-CreateSimpleURLLoaderWithVariationsHeadersUnknownSignedIn(
+CreateSimpleURLLoaderWithVariationsHeaderUnknownSignedIn(
     std::unique_ptr<network::ResourceRequest> request,
     InIncognito incognito,
     const net::NetworkTrafficAnnotationTag& annotation_tag) {
-  return CreateSimpleURLLoaderWithVariationsHeaders(
+  return CreateSimpleURLLoaderWithVariationsHeader(
       std::move(request), incognito, SignedIn::kNo, annotation_tag);
 }
 
-bool ShouldAppendVariationHeaders(const GURL& url) {
-  if (!url.is_valid()) {
-    LogUrlValidationHistogram(INVALID_URL);
-    return false;
-  }
-  if (!url.SchemeIsHTTPOrHTTPS()) {
-    LogUrlValidationHistogram(NEITHER_HTTP_HTTPS);
-    return false;
-  }
-  if (!IsGoogleDomain(url)) {
-    LogUrlValidationHistogram(NOT_GOOGLE_DOMAIN);
-    return false;
-  }
-  // We check https here, rather than before the IsGoogleDomain() check, to know
-  // how many Google domains are being rejected by the change to https only.
-  if (!url.SchemeIs("https")) {
-    LogUrlValidationHistogram(IS_GOOGLE_NOT_HTTPS);
-    return false;
-  }
-  LogUrlValidationHistogram(SHOULD_APPEND);
-  return true;
+bool IsVariationsHeader(const std::string& header_name) {
+  return header_name == kClientDataHeader;
+}
+
+bool HasVariationsHeader(const network::ResourceRequest& request) {
+  return !request.client_data_header.empty();
+}
+
+bool ShouldAppendVariationsHeaderForTesting(const GURL& url) {
+  return ShouldAppendVariationsHeader(url);
 }
 
 }  // namespace variations
diff --git a/chromium/components/variations/net/variations_http_headers.h b/chromium/components/variations/net/variations_http_headers.h
index 4530a6d773f..a25f45d1c26 100644
--- a/chromium/components/variations/net/variations_http_headers.h
+++ b/chromium/components/variations/net/variations_http_headers.h
@@ -8,15 +8,17 @@
 #include <memory>
 #include <set>
 #include <string>
+#include <vector>
 
 namespace net {
-class HttpRequestHeaders;
 struct NetworkTrafficAnnotationTag;
+struct RedirectInfo;
 class URLRequest;
 }
 
 namespace network {
 struct ResourceRequest;
+struct ResourceResponseHead;
 class SimpleURLLoader;
 }  // namespace network
 
@@ -28,10 +30,7 @@ enum class InIncognito { kNo, kYes };
 
 enum class SignedIn { kNo, kYes };
 
-// The name string for the header for variations information.
-extern const char kClientDataHeader[];
-
-// Adds Chrome experiment and metrics state as custom headers to |headers|.
+// Adds Chrome experiment and metrics state as custom headers to |request|.
 // The content of the headers will depend on |incognito| and |signed_in|
 // parameters. It is fine to pass SignedIn::NO if the state is not known to the
 // caller. This will prevent addition of ids of type
@@ -39,46 +38,79 @@ extern const char kClientDataHeader[];
 // from the variations server. These headers are never transmitted to non-Google
 // web sites, which is checked based on the destination |url|.
 // Returns true if custom headers are added. Returns false otherwise.
-bool AppendVariationHeaders(const GURL& url,
+bool AppendVariationsHeader(const GURL& url,
+                            InIncognito incognito,
+                            SignedIn signed_in,
+                            network::ResourceRequest* request);
+
+// TODO(toyoshim): Remove this deprecated API that takes net::URLRequest* once
+// all callers are removed after NetworkService being fully enabled, or migrated
+// to use SimpleURLLoader. See, crbug.com/773295.
+bool AppendVariationsHeader(const GURL& url,
                             InIncognito incognito,
                             SignedIn signed_in,
-                            net::HttpRequestHeaders* headers);
+                            net::URLRequest* request);
+
+// Similar to functions above, but uses specified |variations_header| as the
+// custom header value. You should not generally need to use this.
+bool AppendVariationsHeaderWithCustomValue(const GURL& url,
+                                           InIncognito incognito,
+                                           const std::string& variations_header,
+                                           network::ResourceRequest* request);
 
-// Adds Chrome experiment and metrics state as custom headers to |headers|
+// Adds Chrome experiment and metrics state as a custom header to |request|
 // when the signed-in state is not known to the caller; See above for details.
-bool AppendVariationHeadersUnknownSignedIn(const GURL& url,
+bool AppendVariationsHeaderUnknownSignedIn(const GURL& url,
                                            InIncognito incognito,
-                                           net::HttpRequestHeaders* headers);
+                                           network::ResourceRequest* request);
 
-// Strips the variation header if |new_location| does not point to a location
+// TODO(toyoshim): Remove this deprecated API that takes net::URLRequest* once
+// all callers are removed after NetworkService being fully enabled, or migrated
+// to use SimpleURLLoader. See, crbug.com/773295.
+bool AppendVariationsHeaderUnknownSignedIn(const GURL& url,
+                                           InIncognito incognito,
+                                           net::URLRequest* request);
+
+// Removes the variations header for requests when a redirect to a non-Google
+// URL occurs.
+void RemoveVariationsHeaderIfNeeded(
+    const net::RedirectInfo& redirect_info,
+    const network::ResourceResponseHead& response_head,
+    std::vector<std::string>* to_be_removed_headers);
+
+// Strips the variations header if |new_location| does not point to a location
 // that should receive it. This is being called by the ChromeNetworkDelegate.
-// Components calling AppendVariationsHeaders() don't need to take care of this.
-void StripVariationHeaderIfNeeded(const GURL& new_location,
-                                  net::URLRequest* request);
+// Components calling AppendVariationsHeader() don't need to take care of this.
+void StripVariationsHeaderIfNeeded(const GURL& new_location,
+                                   net::URLRequest* request);
 
-// Creates a SimpleURLLoader that will include variations headers for requests
-// to Google and ensures they're removed if a redirect to a non-Google URL
-// occurs.
+// Creates a SimpleURLLoader that will include the variations header for
+// requests to Google and ensures they're removed if a redirect to a non-Google
+// URL occurs.
 std::unique_ptr<network::SimpleURLLoader>
-CreateSimpleURLLoaderWithVariationsHeaders(
+CreateSimpleURLLoaderWithVariationsHeader(
     std::unique_ptr<network::ResourceRequest> request,
     InIncognito incognito,
     SignedIn signed_in,
     const net::NetworkTrafficAnnotationTag& annotation_tag);
 
-// Creates a SimpleURLLoader that will include variations headers for requests
-// to Google when the signed-in state is unknown and ensures they're removed
-// if a redirect to a non-Google URL occurs.
+// Creates a SimpleURLLoader that will include the variations header for
+// requests to Google when the signed-in state is unknown and ensures they're
+// removed if a redirect to a non-Google URL occurs.
 std::unique_ptr<network::SimpleURLLoader>
-CreateSimpleURLLoaderWithVariationsHeadersUnknownSignedIn(
+CreateSimpleURLLoaderWithVariationsHeaderUnknownSignedIn(
     std::unique_ptr<network::ResourceRequest> request,
     InIncognito incognito,
     const net::NetworkTrafficAnnotationTag& annotation_tag);
 
-// Checks whether variation headers should be appended to requests to the
-// specified |url|. Returns true for google.<TLD> and youtube.<TLD> URLs with
-// the https scheme.
-bool ShouldAppendVariationHeaders(const GURL& url);
+// Checks if |header_name| is one for the variations header.
+bool IsVariationsHeader(const std::string& header_name);
+
+// Checks if |request| contains the variations header.
+bool HasVariationsHeader(const network::ResourceRequest& request);
+
+// Calls the internal ShouldAppendVariationsHeader() for testing.
+bool ShouldAppendVariationsHeaderForTesting(const GURL& url);
 
 }  // namespace variations
 
diff --git a/chromium/components/variations/net/variations_http_headers_unittest.cc b/chromium/components/variations/net/variations_http_headers_unittest.cc
index 87dfc2dc533..a07883107ad 100644
--- a/chromium/components/variations/net/variations_http_headers_unittest.cc
+++ b/chromium/components/variations/net/variations_http_headers_unittest.cc
@@ -13,7 +13,7 @@
 
 namespace variations {
 
-TEST(VariationsHttpHeadersTest, ShouldAppendHeaders) {
+TEST(VariationsHttpHeadersTest, ShouldAppendVariationsHeader) {
   struct {
     const char* url;
     bool should_append_headers;
@@ -154,7 +154,8 @@ TEST(VariationsHttpHeadersTest, ShouldAppendHeaders) {
 
   for (size_t i = 0; i < base::size(cases); ++i) {
     const GURL url(cases[i].url);
-    EXPECT_EQ(cases[i].should_append_headers, ShouldAppendVariationHeaders(url))
+    EXPECT_EQ(cases[i].should_append_headers,
+              ShouldAppendVariationsHeaderForTesting(url))
         << url;
   }
 }
diff --git a/chromium/components/variations/platform_field_trials.h b/chromium/components/variations/platform_field_trials.h
index 3a7f64238f0..bb010fee9a6 100644
--- a/chromium/components/variations/platform_field_trials.h
+++ b/chromium/components/variations/platform_field_trials.h
@@ -29,6 +29,10 @@ class PlatformFieldTrials {
       bool has_seed,
       base::FeatureList* feature_list) = 0;
 
+  // Register any synthetic field trials. Will be called later than the above
+  // methods, in particular after g_browser_process is available..
+  virtual void RegisterSyntheticTrials() {}
+
  private:
   DISALLOW_COPY_AND_ASSIGN(PlatformFieldTrials);
 };
diff --git a/chromium/components/variations/processed_study.cc b/chromium/components/variations/processed_study.cc
index e207ba4d75a..b8abc438682 100644
--- a/chromium/components/variations/processed_study.cc
+++ b/chromium/components/variations/processed_study.cc
@@ -55,11 +55,11 @@ bool ValidateStudyAndComputeTotalProbability(
       return false;
     }
 
-    // Note: This checks for ACTIVATION_EXPLICIT, since there is no reason to
-    // have this association with ACTIVATION_AUTO (where the trial starts
+    // Note: This checks for ACTIVATE_ON_QUERY, since there is no reason to
+    // have this association with ACTIVATE_ON_STARTUP (where the trial starts
     // active), as well as allowing flexibility to disable this behavior in the
     // future from the server by introducing a new activation type.
-    if (study.activation_type() == Study_ActivationType_ACTIVATION_EXPLICIT) {
+    if (study.activation_type() == Study_ActivationType_ACTIVATE_ON_QUERY) {
       const auto& features = experiment.feature_association();
       for (int i = 0; i < features.enable_feature_size(); ++i) {
         features_to_associate.insert(features.enable_feature(i));
diff --git a/chromium/components/variations/proto/study.proto b/chromium/components/variations/proto/study.proto
index 0169db04e26..0993802180c 100644
--- a/chromium/components/variations/proto/study.proto
+++ b/chromium/components/variations/proto/study.proto
@@ -334,10 +334,10 @@ message Study {
   enum ActivationType {
     // The study will be activated when its state is queried by the client.
     // This is recommended for most studies that include client code.
-    ACTIVATION_EXPLICIT  = 0;
+    ACTIVATE_ON_QUERY = 0;
     // The study will be automatically activated when it is created. This
     // is recommended for studies that do not have any client logic.
-    ACTIVATION_AUTO      = 1;
+    ACTIVATE_ON_STARTUP = 1;
   }
 
   // Activation type for this study. Defaults to ACTIVATION_EXPLICIT if omitted.
diff --git a/chromium/components/variations/service/variations_field_trial_creator.cc b/chromium/components/variations/service/variations_field_trial_creator.cc
index c1622956f5d..f98bbbcd0cb 100644
--- a/chromium/components/variations/service/variations_field_trial_creator.cc
+++ b/chromium/components/variations/service/variations_field_trial_creator.cc
@@ -15,6 +15,7 @@
 #include <vector>
 
 #include "base/base_switches.h"
+#include "base/bind.h"
 #include "base/build_time.h"
 #include "base/command_line.h"
 #include "base/metrics/histogram_functions.h"
diff --git a/chromium/components/variations/service/variations_field_trial_creator_unittest.cc b/chromium/components/variations/service/variations_field_trial_creator_unittest.cc
index c1088cdadb3..3910b35828c 100644
--- a/chromium/components/variations/service/variations_field_trial_creator_unittest.cc
+++ b/chromium/components/variations/service/variations_field_trial_creator_unittest.cc
@@ -30,7 +30,6 @@
 #include "testing/gtest/include/gtest/gtest.h"
 
 #if defined(OS_ANDROID)
-#include "components/variations/android/variations_seed_bridge.h"
 #include "components/variations/seed_response.h"
 #endif  // OS_ANDROID
 
@@ -99,6 +98,7 @@ VariationsSeed CreateTestSeedWithCountryFilter() {
   Study* study = seed.mutable_study(0);
   Study::Filter* filter = study->mutable_filter();
   filter->add_country(kTestSeedCountry);
+  filter->add_platform(Study::PLATFORM_ANDROID);
   return seed;
 }
 
diff --git a/chromium/components/variations/service/variations_service.cc b/chromium/components/variations/service/variations_service.cc
index 6c53f8b5d2d..0583214e3de 100644
--- a/chromium/components/variations/service/variations_service.cc
+++ b/chromium/components/variations/service/variations_service.cc
@@ -25,6 +25,7 @@
 #include "base/task/post_task.h"
 #include "base/task_runner_util.h"
 #include "base/timer/elapsed_timer.h"
+#include "base/trace_event/trace_event.h"
 #include "base/values.h"
 #include "base/version.h"
 #include "build/build_config.h"
@@ -502,11 +503,11 @@ bool VariationsService::DoFetchFromURL(const GURL& url, bool is_http_retry) {
 
   safe_seed_manager_.RecordFetchStarted();
 
-  // Normally, there shouldn't be a |pending_request_| when this fires. However
-  // it's not impossible - for example if Chrome was paused (e.g. in a debugger
-  // or if the machine was suspended) and OnURLFetchComplete() hasn't had a
-  // chance to run yet from the previous request. In this case, don't start a
-  // new request and just let the previous one finish.
+  // Normally, there shouldn't be a |pending_seed_request_| when this fires.
+  // However it's not impossible - for example if Chrome was paused (e.g. in a
+  // debugger or if the machine was suspended) and OnURLFetchComplete() hasn't
+  // had a chance to run yet from the previous request. In this case, don't
+  // start a new request and just let the previous one finish.
   if (pending_seed_request_)
     return false;
 
@@ -692,6 +693,7 @@ void VariationsService::OnSimpleLoaderRedirect(
 void VariationsService::OnSimpleLoaderCompleteOrRedirect(
     std::unique_ptr<std::string> response_body,
     bool was_redirect) {
+  TRACE_EVENT0("browser", "VariationsService::OnSimpleLoaderCompleteOrRedirect");
   const bool is_first_request = !initial_request_completed_;
   initial_request_completed_ = true;
 
@@ -918,6 +920,10 @@ void VariationsService::OverrideCachedUIStrings() {
   field_trial_creator_.OverrideCachedUIStrings();
 }
 
+void VariationsService::CancelCurrentRequestForTesting() {
+  pending_seed_request_.reset();
+}
+
 std::string VariationsService::GetStoredPermanentCountry() {
   const base::ListValue* list_value =
       local_state_->GetList(prefs::kVariationsPermanentConsistencyCountry);
diff --git a/chromium/components/variations/service/variations_service.h b/chromium/components/variations/service/variations_service.h
index 217a7c56457..bc5fd826b0c 100644
--- a/chromium/components/variations/service/variations_service.h
+++ b/chromium/components/variations/service/variations_service.h
@@ -176,6 +176,11 @@ class VariationsService
   // Exposed for testing.
   void GetClientFilterableStateForVersionCalledForTesting();
 
+  web_resource::ResourceRequestAllowedNotifier*
+  GetResourceRequestAllowedNotifierForTesting() {
+    return resource_request_allowed_notifier_.get();
+  }
+
   // Wrapper around VariationsFieldTrialCreator::SetupFieldTrials().
   bool SetupFieldTrials(const char* kEnableGpuBenchmarking,
                         const char* kEnableFeatures,
@@ -190,6 +195,9 @@ class VariationsService
 
   int request_count() const { return request_count_; }
 
+  // Cancels the currently pending fetch request.
+  void CancelCurrentRequestForTesting();
+
  protected:
   // Starts the fetching process once, where |OnURLFetchComplete| is called with
   // the response. This calls DoFetchToURL with the set url.
diff --git a/chromium/components/variations/service/variations_service_unittest.cc b/chromium/components/variations/service/variations_service_unittest.cc
index 57eac53d3bb..0eb1a64ca37 100644
--- a/chromium/components/variations/service/variations_service_unittest.cc
+++ b/chromium/components/variations/service/variations_service_unittest.cc
@@ -11,12 +11,12 @@
 #include <vector>
 
 #include "base/base64.h"
+#include "base/bind.h"
 #include "base/feature_list.h"
 #include "base/json/json_string_value_serializer.h"
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "base/run_loop.h"
-#include "base/sha1.h"
 #include "base/stl_util.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_split.h"
diff --git a/chromium/components/variations/study_filtering.cc b/chromium/components/variations/study_filtering.cc
index 6f1e21773de..54aa57b04e6 100644
--- a/chromium/components/variations/study_filtering.cc
+++ b/chromium/components/variations/study_filtering.cc
@@ -107,10 +107,6 @@ bool CheckStudyLocale(const Study::Filter& filter, const std::string& locale) {
 }
 
 bool CheckStudyPlatform(const Study::Filter& filter, Study::Platform platform) {
-  // An empty platform list matches all platforms.
-  if (filter.platform_size() == 0)
-    return true;
-
   for (int i = 0; i < filter.platform_size(); ++i) {
     if (filter.platform(i) == platform)
       return true;
diff --git a/chromium/components/variations/study_filtering_unittest.cc b/chromium/components/variations/study_filtering_unittest.cc
index 184747fda93..2b11e1afc04 100644
--- a/chromium/components/variations/study_filtering_unittest.cc
+++ b/chromium/components/variations/study_filtering_unittest.cc
@@ -222,10 +222,10 @@ TEST(VariationsStudyFilteringTest, CheckStudyPlatform) {
   Study::Filter filter;
 
   // Check in the forwarded order. The loop cond is <= base::size(platforms)
-  // instead of < so that the result of adding the last channel gets checked.
+  // instead of < so that the result of adding the last platform gets checked.
   for (size_t i = 0; i <= base::size(platforms); ++i) {
     for (size_t j = 0; j < base::size(platforms); ++j) {
-      const bool expected = platform_added[j] || filter.platform_size() == 0;
+      const bool expected = platform_added[j];
       const bool result = internal::CheckStudyPlatform(filter, platforms[j]);
       EXPECT_EQ(expected, result) << "Case " << i << "," << j << " failed!";
     }
@@ -241,7 +241,7 @@ TEST(VariationsStudyFilteringTest, CheckStudyPlatform) {
   memset(&platform_added, 0, sizeof(platform_added));
   for (size_t i = 0; i <= base::size(platforms); ++i) {
     for (size_t j = 0; j < base::size(platforms); ++j) {
-      const bool expected = platform_added[j] || filter.platform_size() == 0;
+      const bool expected = platform_added[j];
       const bool result = internal::CheckStudyPlatform(filter, platforms[j]);
       EXPECT_EQ(expected, result) << "Case " << i << "," << j << " failed!";
     }
@@ -575,6 +575,7 @@ TEST(VariationsStudyFilteringTest, FilterAndValidateStudiesWithCountry) {
     study->set_default_experiment_name("Default");
     AddExperiment("Default", 100, study);
     study->set_consistency(test.consistency);
+    study->mutable_filter()->add_platform(Study::PLATFORM_ANDROID);
     if (test.filter_country)
       study->mutable_filter()->add_country(test.filter_country);
     if (test.filter_exclude_country)
@@ -585,7 +586,7 @@ TEST(VariationsStudyFilteringTest, FilterAndValidateStudiesWithCountry) {
     client_state.reference_date = base::Time::Now();
     client_state.version = base::Version("20.0.0.0");
     client_state.channel = Study::STABLE;
-    client_state.form_factor = Study::DESKTOP;
+    client_state.form_factor = Study::PHONE;
     client_state.platform = Study::PLATFORM_ANDROID;
     client_state.session_consistency_country = kSessionCountry;
     client_state.permanent_consistency_country = kPermanentCountry;
diff --git a/chromium/components/variations/variations_experiment_util.cc b/chromium/components/variations/variations_experiment_util.cc
deleted file mode 100644
index 9cf78bbabc0..00000000000
--- a/chromium/components/variations/variations_experiment_util.cc
+++ /dev/null
@@ -1,54 +0,0 @@
-// Copyright 2013 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "components/variations/variations_experiment_util.h"
-
-#include <vector>
-
-#include "base/logging.h"
-#include "base/strings/stringprintf.h"
-#include "base/strings/utf_string_conversions.h"
-#include "base/time/time.h"
-
-namespace variations {
-
-const base::char16 kExperimentLabelSeparator = ';';
-
-namespace {
-
-const char* const kDays[] = {"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"};
-
-const char* const kMonths[] = {"Jan", "Feb", "Mar", "Apr", "May", "Jun",
-                               "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
-
-}  // namespace
-
-base::string16 BuildExperimentDateString(const base::Time& current_time) {
-  // The Google Update experiment_labels timestamp format is:
-  // "DAY, DD0 MON YYYY HH0:MI0:SE0 TZ"
-  //  DAY = 3 character day of week,
-  //  DD0 = 2 digit day of month,
-  //  MON = 3 character month of year,
-  //  YYYY = 4 digit year,
-  //  HH0 = 2 digit hour,
-  //  MI0 = 2 digit minute,
-  //  SE0 = 2 digit second,
-  //  TZ = 3 character timezone
-  base::Time::Exploded then = {};
-  current_time.UTCExplode(&then);
-  then.year += 1;
-  DCHECK(then.HasValidValues());
-
-  return base::UTF8ToUTF16(
-      base::StringPrintf("%s, %02d %s %d %02d:%02d:%02d GMT",
-                         kDays[then.day_of_week],
-                         then.day_of_month,
-                         kMonths[then.month - 1],
-                         then.year,
-                         then.hour,
-                         then.minute,
-                         then.second));
-}
-
-}  // namespace variations
diff --git a/chromium/components/variations/variations_experiment_util.h b/chromium/components/variations/variations_experiment_util.h
deleted file mode 100644
index c9c23f4006b..00000000000
--- a/chromium/components/variations/variations_experiment_util.h
+++ /dev/null
@@ -1,25 +0,0 @@
-// Copyright 2013 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef COMPONENTS_VARIATIONS_VARIATIONS_EXPERIMENT_UTIL_H_
-#define COMPONENTS_VARIATIONS_VARIATIONS_EXPERIMENT_UTIL_H_
-
-#include "base/strings/string16.h"
-
-namespace base {
-class Time;
-}
-
-namespace variations {
-
-// The separator used to separate items in experiment labels.
-extern const base::char16 kExperimentLabelSeparator;
-
-// Constructs a date string in the format understood by Google Update for the
-// |current_time| plus one year.
-base::string16 BuildExperimentDateString(const base::Time& current_time);
-
-}  // namespace variations
-
-#endif  // COMPONENTS_VARIATIONS_VARIATIONS_EXPERIMENT_UTIL_H_
diff --git a/chromium/components/variations/variations_http_header_provider.cc b/chromium/components/variations/variations_http_header_provider.cc
index 29084615b68..e8a1a389cbf 100644
--- a/chromium/components/variations/variations_http_header_provider.cc
+++ b/chromium/components/variations/variations_http_header_provider.cc
@@ -40,7 +40,7 @@ namespace variations {
 // ChromeContentBrowserClient::CreateURLLoaderThrottles() by also adding a
 // GoogleURLLoaderThrottle to a content::URLLoaderThrottle vector.
 // 3. SimpleURLLoader in browser, it is implemented in a SimpleURLLoader wrapper
-// function variations::CreateSimpleURLLoaderWithVariationsHeaders().
+// function variations::CreateSimpleURLLoaderWithVariationsHeader().
 
 // static
 VariationsHttpHeaderProvider* VariationsHttpHeaderProvider::GetInstance() {
@@ -74,7 +74,7 @@ std::string VariationsHttpHeaderProvider::GetVariationsString() {
     base::AutoLock scoped_lock(lock_);
     for (const VariationIDEntry& entry : GetAllVariationIds()) {
       if (entry.second == GOOGLE_WEB_PROPERTIES) {
-        ids_string.append(base::IntToString(entry.first));
+        ids_string.append(base::NumberToString(entry.first));
         ids_string.push_back(' ');
       }
     }
@@ -82,6 +82,28 @@ std::string VariationsHttpHeaderProvider::GetVariationsString() {
   return ids_string;
 }
 
+std::vector<VariationID> VariationsHttpHeaderProvider::GetVariationsVector(
+    IDCollectionKey key) {
+  InitVariationIDsCacheIfNeeded();
+
+  // Get all the active variation ids while holding the lock.
+  std::set<VariationIDEntry> all_variation_ids;
+  {
+    base::AutoLock scoped_lock(lock_);
+    all_variation_ids = GetAllVariationIds();
+  }
+
+  // Copy the requested variations to the output vector. Note that the ids will
+  // be in sorted order because they're coming from a std::set.
+  std::vector<VariationID> result;
+  result.reserve(all_variation_ids.size());
+  for (const VariationIDEntry& entry : all_variation_ids) {
+    if (entry.second == key)
+      result.push_back(entry.first);
+  }
+  return result;
+}
+
 VariationsHttpHeaderProvider::ForceIdsResult
 VariationsHttpHeaderProvider::ForceVariationIds(
     const std::vector<std::string>& variation_ids,
diff --git a/chromium/components/variations/variations_http_header_provider.h b/chromium/components/variations/variations_http_header_provider.h
index b29fcd07cdd..85b9d737d0d 100644
--- a/chromium/components/variations/variations_http_header_provider.h
+++ b/chromium/components/variations/variations_http_header_provider.h
@@ -57,6 +57,10 @@ class VariationsHttpHeaderProvider : public base::FieldTrialList::Observer,
   // a leading and trailing space, e.g. " 123 234 345 ".
   std::string GetVariationsString();
 
+  // Returns the collection of of variation ids matching the given |key|. Each
+  // entry in the returned vector will be unique.
+  std::vector<VariationID> GetVariationsVector(IDCollectionKey key);
+
   // Result of ForceVariationIds() call.
   enum class ForceIdsResult {
     SUCCESS,
@@ -95,6 +99,8 @@ class VariationsHttpHeaderProvider : public base::FieldTrialList::Observer,
                            OnFieldTrialGroupFinalized);
   FRIEND_TEST_ALL_PREFIXES(VariationsHttpHeaderProviderTest,
                            GetVariationsString);
+  FRIEND_TEST_ALL_PREFIXES(VariationsHttpHeaderProviderTest,
+                           GetVariationsVector);
 
   VariationsHttpHeaderProvider();
   ~VariationsHttpHeaderProvider() override;
diff --git a/chromium/components/variations/variations_http_header_provider_unittest.cc b/chromium/components/variations/variations_http_header_provider_unittest.cc
index 70d1cbe8f4b..6e7823def3f 100644
--- a/chromium/components/variations/variations_http_header_provider_unittest.cc
+++ b/chromium/components/variations/variations_http_header_provider_unittest.cc
@@ -184,4 +184,25 @@ TEST_F(VariationsHttpHeaderProviderTest, GetVariationsString) {
   EXPECT_EQ(" 100 123 124 200 ", provider.GetVariationsString());
 }
 
+TEST_F(VariationsHttpHeaderProviderTest, GetVariationsVector) {
+  base::test::ScopedTaskEnvironment task_environment;
+  base::FieldTrialList field_trial_list(nullptr);
+
+  CreateTrialAndAssociateId("t1", "g1", GOOGLE_WEB_PROPERTIES, 121);
+  CreateTrialAndAssociateId("t2", "g2", GOOGLE_WEB_PROPERTIES, 122);
+  CreateTrialAndAssociateId("t3", "g3", GOOGLE_WEB_PROPERTIES_TRIGGER, 123);
+  CreateTrialAndAssociateId("t4", "g4", GOOGLE_WEB_PROPERTIES_TRIGGER, 124);
+  CreateTrialAndAssociateId("t5", "g5", GOOGLE_WEB_PROPERTIES_SIGNED_IN, 125);
+
+  VariationsHttpHeaderProvider provider;
+  provider.ForceVariationIds({"100", "200", "t101"}, "");
+
+  EXPECT_EQ((std::vector<VariationID>{100, 121, 122, 200}),
+            provider.GetVariationsVector(GOOGLE_WEB_PROPERTIES));
+  EXPECT_EQ((std::vector<VariationID>{101, 123, 124}),
+            provider.GetVariationsVector(GOOGLE_WEB_PROPERTIES_TRIGGER));
+  EXPECT_EQ((std::vector<VariationID>{125}),
+            provider.GetVariationsVector(GOOGLE_WEB_PROPERTIES_SIGNED_IN));
+}
+
 }  // namespace variations
diff --git a/chromium/components/variations/variations_id_collection_unittest.cc b/chromium/components/variations/variations_id_collection_unittest.cc
index a17343d9b65..2c4f4bbb5c9 100644
--- a/chromium/components/variations/variations_id_collection_unittest.cc
+++ b/chromium/components/variations/variations_id_collection_unittest.cc
@@ -7,6 +7,7 @@
 #include <memory>
 #include <vector>
 
+#include "base/bind.h"
 #include "base/metrics/field_trial.h"
 #include "base/run_loop.h"
 #include "base/test/scoped_task_environment.h"
diff --git a/chromium/components/variations/variations_murmur_hash.h b/chromium/components/variations/variations_murmur_hash.h
index 9ec77ad416e..b3e7458a82d 100644
--- a/chromium/components/variations/variations_murmur_hash.h
+++ b/chromium/components/variations/variations_murmur_hash.h
@@ -32,9 +32,9 @@ class VariationsMurmurHash {
   // it produces the same results that MurmurHash3_x86_32 would produce on a
   // little-endian platform.
   //
-  // |length| is the number of bytes to hash. It mustn't exceed
-  // padded_data.size() * 4. If length % 4 != 0, Hash will consume the
-  // less-significant bytes of the last uint32_t first.
+  // |length| is the number of bytes to hash. It mustn't exceed data.size() * 4.
+  // If length % 4 != 0, Hash will consume the less-significant bytes of the
+  // last uint32_t first.
   //
   // MurmurHash3_x86_32 takes a seed, for which 0 is the typical value. Hash
   // hard-codes the seed to 0, since NormalizedMurmurHashEntropyProvider doesn't
diff --git a/chromium/components/variations/variations_request_scheduler_mobile.h b/chromium/components/variations/variations_request_scheduler_mobile.h
index 5b46f1f1286..838373fb4ac 100644
--- a/chromium/components/variations/variations_request_scheduler_mobile.h
+++ b/chromium/components/variations/variations_request_scheduler_mobile.h
@@ -8,6 +8,7 @@
 #include "base/bind.h"
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
+#include "base/timer/timer.h"
 #include "components/variations/variations_request_scheduler.h"
 
 class PrefService;
diff --git a/chromium/components/variations/variations_seed_processor.cc b/chromium/components/variations/variations_seed_processor.cc
index 3bc232fdbdc..58e41585210 100644
--- a/chromium/components/variations/variations_seed_processor.cc
+++ b/chromium/components/variations/variations_seed_processor.cc
@@ -84,12 +84,12 @@ void ForceExperimentState(
     base::FieldTrial* trial) {
   RegisterExperimentParams(study, experiment);
   RegisterVariationIds(experiment, study.name());
-  if (study.activation_type() == Study_ActivationType_ACTIVATION_AUTO) {
+  if (study.activation_type() == Study_ActivationType_ACTIVATE_ON_STARTUP) {
     // This call must happen after all params have been registered for the
     // trial. Otherwise, since we look up params by trial and group name, the
     // params won't be registered under the correct key.
     trial->group();
-    // UI Strings can only be overridden from ACTIVATION_AUTO experiments.
+    // UI Strings can only be overridden from ACTIVATE_ON_STARTUP experiments.
     ApplyUIStringOverrides(experiment, override_callback);
   }
 }
@@ -297,7 +297,7 @@ void VariationsSeedProcessor::CreateTrialFromStudy(
   if (enables_or_disables_features)
     RegisterFeatureOverrides(processed_study, trial.get(), feature_list);
 
-  if (study.activation_type() == Study_ActivationType_ACTIVATION_AUTO) {
+  if (study.activation_type() == Study_ActivationType_ACTIVATE_ON_STARTUP) {
     // This call must happen after all params have been registered for the
     // trial. Otherwise, since we look up params by trial and group name, the
     // params won't be registered under the correct key.
@@ -308,7 +308,7 @@ void VariationsSeedProcessor::CreateTrialFromStudy(
     if (!has_overrides)
       return;
 
-    // UI Strings can only be overridden from ACTIVATION_AUTO experiments.
+    // UI Strings can only be overridden from ACTIVATE_ON_STARTUP experiments.
     int experiment_index = processed_study.GetExperimentIndexByName(group_name);
     // If the chosen experiment was not found in the study, simply return.
     // Although not normally expected, but could happen in exception cases, see
diff --git a/chromium/components/variations/variations_seed_processor_unittest.cc b/chromium/components/variations/variations_seed_processor_unittest.cc
index fcc5fb1c48f..f41d36ecc39 100644
--- a/chromium/components/variations/variations_seed_processor_unittest.cc
+++ b/chromium/components/variations/variations_seed_processor_unittest.cc
@@ -306,7 +306,7 @@ TEST_F(VariationsSeedProcessorTest, OverrideUIStrings) {
   Study study;
   study.set_name("Study1");
   study.set_default_experiment_name("B");
-  study.set_activation_type(Study_ActivationType_ACTIVATION_AUTO);
+  study.set_activation_type(Study_ActivationType_ACTIVATE_ON_STARTUP);
 
   Study_Experiment* experiment1 = AddExperiment("A", 0, &study);
   Study_Experiment_OverrideUIString* override =
@@ -339,7 +339,7 @@ TEST_F(VariationsSeedProcessorTest, OverrideUIStringsWithForcingFlag) {
   Study study = CreateStudyWithFlagGroups(100, 0, 0);
   ASSERT_EQ(kForcingFlag1, study.experiment(1).forcing_flag());
 
-  study.set_activation_type(Study_ActivationType_ACTIVATION_AUTO);
+  study.set_activation_type(Study_ActivationType_ACTIVATE_ON_STARTUP);
   Study_Experiment_OverrideUIString* override =
       study.mutable_experiment(1)->add_override_ui_string();
   override->set_name_hash(1234);
@@ -451,7 +451,7 @@ TEST_F(VariationsSeedProcessorTest, ValidateStudyWithAssociatedFeatures) {
 
   // Setting a different activation type should result in empty
   // |associated_features|.
-  study.set_activation_type(Study_ActivationType_ACTIVATION_AUTO);
+  study.set_activation_type(Study_ActivationType_ACTIVATE_ON_STARTUP);
   EXPECT_TRUE(processed_study.Init(&study, false));
   EXPECT_THAT(processed_study.associated_features(), IsEmpty());
 }
@@ -539,14 +539,14 @@ TEST_F(VariationsSeedProcessorTest, StartsActive) {
   study2->set_default_experiment_name("Default");
   AddExperiment("BB", 100, study2);
   AddExperiment("Default", 0, study2);
-  study2->set_activation_type(Study_ActivationType_ACTIVATION_AUTO);
+  study2->set_activation_type(Study_ActivationType_ACTIVATE_ON_STARTUP);
 
   Study* study3 = seed.add_study();
   study3->set_name("C");
   study3->set_default_experiment_name("Default");
   AddExperiment("CC", 100, study3);
   AddExperiment("Default", 0, study3);
-  study3->set_activation_type(Study_ActivationType_ACTIVATION_EXPLICIT);
+  study3->set_activation_type(Study_ActivationType_ACTIVATE_ON_QUERY);
 
   ClientFilterableState client_state;
   client_state.locale = "en-CA";
@@ -561,8 +561,8 @@ TEST_F(VariationsSeedProcessorTest, StartsActive) {
                                       override_callback_.callback(), nullptr,
                                       &feature_list_);
 
-  // Non-specified and ACTIVATION_EXPLICIT should not start active, but
-  // ACTIVATION_AUTO should.
+  // Non-specified and ACTIVATE_ON_QUERY should not start active, but
+  // ACTIVATE_ON_STARTUP should.
   EXPECT_FALSE(base::FieldTrialList::IsTrialActive("A"));
   EXPECT_TRUE(base::FieldTrialList::IsTrialActive("B"));
   EXPECT_FALSE(base::FieldTrialList::IsTrialActive("C"));
@@ -583,7 +583,7 @@ TEST_F(VariationsSeedProcessorTest, StartsActiveWithFlag) {
   base::FieldTrialList field_trial_list(nullptr);
 
   Study study = CreateStudyWithFlagGroups(100, 0, 0);
-  study.set_activation_type(Study_ActivationType_ACTIVATION_AUTO);
+  study.set_activation_type(Study_ActivationType_ACTIVATE_ON_STARTUP);
 
   EXPECT_TRUE(CreateTrialFromStudy(study));
   EXPECT_TRUE(base::FieldTrialList::IsTrialActive(kFlagStudyName));