1 files changed, 66 insertions, 0 deletions
diff --git a/chromium/media/base/simple_watch_timer.cc b/chromium/media/base/simple_watch_timer.cc
new file mode 100644
index 00000000000..83668dfd7a2
--- /dev/null
+++ b/chromium/media/base/simple_watch_timer.cc
@@ -0,0 +1,66 @@
+// Copyright 2019 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 "media/base/simple_watch_timer.h"
+
+#include "base/location.h"
+#include "media/base/timestamp_constants.h"
+
+namespace media {
+
+namespace {
+
+constexpr base::TimeDelta kQueryInterval =
+    base::TimeDelta::FromMilliseconds(750);
+
+}  // namespace
+
+SimpleWatchTimer::SimpleWatchTimer(TickCB tick_cb,
+                                   GetCurrentTimeCB get_current_time_cb)
+    : tick_cb_(std::move(tick_cb)),
+      get_current_time_cb_(std::move(get_current_time_cb)) {
+  DCHECK(!tick_cb_.is_null());
+  DCHECK(!get_current_time_cb_.is_null());
+}
+
+SimpleWatchTimer::~SimpleWatchTimer() {}
+
+void SimpleWatchTimer::Start() {
+  if (timer_.IsRunning())
+    return;
+
+  last_current_time_ = get_current_time_cb_.Run();
+  timer_.Start(FROM_HERE, kQueryInterval, this, &SimpleWatchTimer::Tick);
+}
+
+void SimpleWatchTimer::Stop() {
+  if (!timer_.IsRunning())
+    return;
+
+  timer_.Stop();
+  Tick();
+}
+
+void SimpleWatchTimer::Tick() {
+  base::TimeDelta current_time = get_current_time_cb_.Run();
+  base::TimeDelta duration;
+  if (last_current_time_ != kNoTimestamp &&
+      last_current_time_ != kInfiniteDuration) {
+    duration = current_time - last_current_time_;
+  }
+  last_current_time_ = current_time;
+
+  // Accumulate watch time if the duration is reasonable.
+  if (duration > base::TimeDelta() && duration < kQueryInterval * 2) {
+    unreported_ms_ += duration.InMilliseconds();
+  }
+
+  // Tick if the accumulated time is about a second.
+  if (unreported_ms_ >= 500) {
+    unreported_ms_ -= 1000;
+    tick_cb_.Run();
+  }
+}
+
+}  // namespace media