Use TimeTicks as much as possible in startup_metric_utils.

components/html_viewer/stats_collection_controller.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/html_viewer/stats_collection_controller.h"
 
 #include "base/command_line.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/metrics/histogram.h"
 #include "base/metrics/statistics_recorder.h"
 #include "base/time/time.h"
 #include "components/startup_metric_utils/browser/startup_metric_utils.h"
 #include "gin/handle.h"
 #include "gin/object_template_builder.h"
 #include "mojo/application/public/cpp/application_impl.h"
 #include "mojo/services/tracing/public/cpp/switches.h"
 #include "third_party/WebKit/public/web/WebKit.h"
 #include "third_party/WebKit/public/web/WebLocalFrame.h"
 
 namespace html_viewer {
 
 namespace {
 
 // Initialize the histogram data using the given startup performance times.
-// TODO(msw): Use TimeTicks to avoid system clock changes: crbug.com/521164
 void GetStartupPerformanceTimesCallbackImpl(
     tracing::StartupPerformanceTimesPtr times) {
   base::StatisticsRecorder::Initialize();
 
   startup_metric_utils::RecordStartupProcessCreationTime(
       base::Time::FromInternalValue(times->shell_process_creation_time));
 
   // TODO(msw): Record the MojoMain() entry point time of mojo:browser instead?
   startup_metric_utils::RecordMainEntryPointTime(
       base::Time::FromInternalValue(times->shell_main_entry_point_time));
 
   // TODO(msw): Determine if this is the first run.
   startup_metric_utils::RecordBrowserMainMessageLoopStart(
-      base::Time::FromInternalValue(times->browser_message_loop_start_time),
+      base::TimeTicks::FromInternalValue(
+          times->browser_message_loop_start_ticks),
       false);
 
   startup_metric_utils::RecordBrowserWindowDisplay(
-      base::Time::FromInternalValue(times->browser_window_display_time));
+      base::TimeTicks::FromInternalValue(times->browser_window_display_ticks));
 
   startup_metric_utils::RecordBrowserOpenTabsDelta(
       base::TimeDelta::FromInternalValue(times->browser_open_tabs_time_delta));
 
   startup_metric_utils::RecordFirstWebContentsMainFrameLoad(
-      base::Time::FromInternalValue(
-          times->first_web_contents_main_frame_load_time));
+      base::TimeTicks::FromInternalValue(
+          times->first_web_contents_main_frame_load_ticks));
 
   startup_metric_utils::RecordFirstWebContentsNonEmptyPaint(
-      base::Time::FromInternalValue(
-          times->first_visually_non_empty_layout_time));
+      base::TimeTicks::FromInternalValue(
+          times->first_visually_non_empty_layout_ticks));
 }
 
 }  // namespace
 
 // static
 gin::WrapperInfo StatsCollectionController::kWrapperInfo = {
     gin::kEmbedderNativeGin};
 
 // static
 tracing::StartupPerformanceDataCollectorPtr StatsCollectionController::Install(
@@ skipping 88 matching lines @@
     histogram->WriteJSON(&histogram_json);
   return histogram_json;
 }
 
 std::string StatsCollectionController::GetBrowserHistogram(
     const std::string& histogram_name) {
   return GetHistogram(histogram_name);
 }
 
 }  // namespace html_viewer