[Page Load Metrics] PageLoadMetrics Mojofication.

chrome/renderer/page_load_metrics/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 "chrome/renderer/page_load_metrics/page_timing_metrics_sender.h"
 
 #include <utility>
 
 #include "base/callback.h"
+#include "base/feature_list.h"
 #include "base/time/time.h"
 #include "base/timer/timer.h"
+#include "chrome/common/chrome_features.h"
 #include "chrome/common/page_load_metrics/page_load_metrics_messages.h"
+#include "chrome/renderer/page_load_metrics/page_timing_sender.h"
 #include "ipc/ipc_sender.h"
 
 namespace page_load_metrics {
 
 namespace {
 const int kInitialTimerDelayMillis = 50;
 const int kTimerDelayMillis = 1000;
 }  // namespace
 
 PageTimingMetricsSender::PageTimingMetricsSender(
     IPC::Sender* ipc_sender,
     int routing_id,
+    PageTimingSender* page_timing_sender,
     std::unique_ptr<base::Timer> timer,
     const PageLoadTiming& initial_timing)
     : ipc_sender_(ipc_sender),
       routing_id_(routing_id),
+      page_timing_sender_(page_timing_sender),
       timer_(std::move(timer)),
       last_timing_(initial_timing),
       metadata_(PageLoadMetadata()) {
   if (!initial_timing.IsEmpty()) {
     // Send an initial IPC relatively early to help track aborts.
     EnsureSendTimer(kInitialTimerDelayMillis);
   }
 }
 
 // On destruction, we want to send any data we have if we have a timer
@@ skipping 30 matching lines @@
 }
 
 void PageTimingMetricsSender::EnsureSendTimer(int delay) {
   if (!timer_->IsRunning())
     timer_->Start(
         FROM_HERE, base::TimeDelta::FromMilliseconds(delay),
         base::Bind(&PageTimingMetricsSender::SendNow, base::Unretained(this)));
 }
 
 void PageTimingMetricsSender::SendNow() {
+  if (base::FeatureList::IsEnabled(features::kPageLoadMetricsMojofication)) {
+    page_timing_sender_->SendTiming(last_timing_, metadata_);

[Zhen Wang, 2017/04/19 18:49:54]

So this actually calls to MetricsRenderFrameObserver::SendTiming(). Can we just
do the following?

page_load_metrics_->UpdateTiming(timing, metadata);

We can also just get the mojo end point here.

+    return;
+  }
   ipc_sender_->Send(new PageLoadMetricsMsg_TimingUpdated(

[Zhen Wang, 2017/04/19 18:56:31]

We do not need to always send this via IPC. The flag can just toggle this:
either send via IPC or Mojo, but not both. So the IPC one is control group and
the Mojo one is experiment group. This can simplify the code on the browser
side.

       routing_id_, last_timing_, metadata_));
 }
 
 }  // namespace page_load_metrics