PageLoadMetrics renderer and browser implementation.

components/page_load_metrics/renderer/page_timing_metrics_sender.cc

+// Copyright 2015 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 "base/callback.h"
+#include "base/time/time.h"
+#include "base/timer/timer.h"
+#include "components/page_load_metrics/common/page_load_metrics_messages.h"
+#include "components/page_load_metrics/renderer/page_timing_metrics_sender.h"
+#include "ipc/ipc_sender.h"
+
+namespace page_load_metrics {
+
+namespace {
+const int kTimerDelayMillis = 1000;
+}  // namespace
+
+PageTimingMetricsSender::PageTimingMetricsSender(IPC::Sender* ipc_sender,
+                                                 int routing_id,
+                                                 scoped_ptr<base::Timer> timer)
+    : ipc_sender_(ipc_sender), routing_id_(routing_id), timer_(timer.Pass()) {}
+
+PageTimingMetricsSender::~PageTimingMetricsSender() {
+  if (timer_->IsRunning()) {
+    timer_->Stop();

[Bryan McQuade, 2015/09/02 18:26:46]

I know I wrote this bit of code, but I think it would benefit from a comment to
explain why we want to force send if the timer is running in the destructor.

[Charlie Harrison, 2015/09/02 18:38:24]

Yes good idea. This took me a little bit to grok.

+    SendNow();
+  }
+}
+
+void PageTimingMetricsSender::Send(const PageLoadTiming& timing) {
+  if (timing == last_timing_)
+    return;
+
+  last_timing_ = timing;
+
+  if (!timer_->IsRunning())
+    timer_->Start(
+        FROM_HERE, base::TimeDelta::FromMilliseconds(kTimerDelayMillis),
+        base::Bind(&PageTimingMetricsSender::SendNow, base::Unretained(this)));
+}
+
+void PageTimingMetricsSender::SendNow() {
+  ipc_sender_->Send(
+      new PageLoadMetricsMsg_TimingUpdated(routing_id_, last_timing_));
+}
+
+}  // namespace page_load_metrics