Separate page load metrics for backgrounded pages

components/page_load_metrics/renderer/metrics_render_frame_observer.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 "components/page_load_metrics/renderer/metrics_render_frame_observer.h"
 
 #include "base/time/time.h"
 #include "base/timer/timer.h"
 #include "components/page_load_metrics/renderer/page_timing_metrics_sender.h"
 #include "content/public/renderer/render_frame.h"
 #include "third_party/WebKit/public/platform/WebURLResponse.h"
 #include "third_party/WebKit/public/web/WebDataSource.h"
 #include "third_party/WebKit/public/web/WebDocument.h"
 #include "third_party/WebKit/public/web/WebLocalFrame.h"
 #include "third_party/WebKit/public/web/WebPerformance.h"
 #include "url/gurl.h"
 
 namespace page_load_metrics {
 
 namespace {
 
 base::TimeDelta ClampDelta(double event, double start) {
   if (event - start < 0)
     event = start;
   return base::Time::FromDoubleT(event) - base::Time::FromDoubleT(start);
 }
 
-} //  namespace
+}  //  namespace
 
 MetricsRenderFrameObserver::MetricsRenderFrameObserver(
     content::RenderFrame* render_frame)
     : content::RenderFrameObserver(render_frame) {}
 
 MetricsRenderFrameObserver::~MetricsRenderFrameObserver() {}
 
 void MetricsRenderFrameObserver::DidChangePerformanceTiming() {
   SendMetrics();
 }
@@ skipping 74 matching lines @@
   timing.load_event_start = ClampDelta(perf.loadEventStart(), start);
   timing.first_layout = ClampDelta(perf.firstLayout(), start);
   return timing;
 }
 
 scoped_ptr<base::Timer> MetricsRenderFrameObserver::CreateTimer() const {
   return make_scoped_ptr(new base::OneShotTimer);
 }
 
 }  // namespace page_load_metrics