BASELINE: Update Chromium to 85.0.4183.14085-based

Change-Id: Iaa42f4680837c57725b1344f108c0196741f6057
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>

1 files changed, 60 insertions, 0 deletions

diff --git a/chromium/base/strings/strcat_internal.h b/chromium/base/strings/strcat_internal.h
new file mode 100644
index 00000000000..f5e52f08667
--- /dev/null
+++ b/chromium/base/strings/strcat_internal.h
@@ -0,0 +1,60 @@
+// Copyright 2020 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 BASE_STRINGS_STRCAT_INTERNAL_H_
+#define BASE_STRINGS_STRCAT_INTERNAL_H_
+
+#include <string>
+
+#include "base/containers/span.h"
+
+namespace base {
+
+namespace internal {
+
+// Reserves an additional amount of capacity in the given string, growing by at
+// least 2x if necessary. Used by StrAppendT().
+//
+// The "at least 2x" growing rule duplicates the exponential growth of
+// std::string. The problem is that most implementations of reserve() will grow
+// exactly to the requested amount instead of exponentially growing like would
+// happen when appending normally. If we didn't do this, an append after the
+// call to StrAppend() would definitely cause a reallocation, and loops with
+// StrAppend() calls would have O(n^2) complexity to execute. Instead, we want
+// StrAppend() to have the same semantics as std::string::append().
+template <typename String>
+void ReserveAdditionalIfNeeded(String* str,
+                               typename String::size_type additional) {
+  const size_t required = str->size() + additional;
+  // Check whether we need to reserve additional capacity at all.
+  if (required <= str->capacity())
+    return;
+
+  str->reserve(std::max(required, str->capacity() * 2));
+}
+
+template <typename DestString, typename InputString>
+void StrAppendT(DestString* dest, span<const InputString> pieces) {
+  size_t additional_size = 0;
+  for (const auto& cur : pieces)
+    additional_size += cur.size();
+  ReserveAdditionalIfNeeded(dest, additional_size);
+
+  for (const auto& cur : pieces)
+    dest->append(cur.data(), cur.size());
+}
+
+template <typename StringT>
+auto StrCatT(span<const StringT> pieces) {
+  std::basic_string<typename StringT::value_type, typename StringT::traits_type>
+      result;
+  StrAppendT(&result, pieces);
+  return result;
+}
+
+}  // namespace internal
+
+}  // namespace base
+
+#endif  // BASE_STRINGS_STRCAT_INTERNAL_H_