[Android] Support startup histogram.

chrome/common/startup_metric_utils.cc

 // Copyright (c) 2012 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/common/startup_metric_utils.h"
 
 #include "base/containers/hash_tables.h"
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
 #include "base/metrics/histogram_base.h"
 #include "base/metrics/statistics_recorder.h"
 #include "base/synchronization/lock.h"
 #include "base/sys_info.h"
 #include "base/time/time.h"
 
 namespace {
 
 // Mark as volatile to defensively make sure usage is thread-safe.
 // Note that at the time of this writing, access is only on the UI thread.
 volatile bool g_non_browser_ui_displayed = false;
 
-const base::Time* MainEntryPointTimeInternal() {
+base::Time* MainEntryPointTimeInternal() {
   static base::Time main_start_time = base::Time::Now();
   return &main_start_time;
 }
 
 typedef base::hash_map<std::string,base::TimeDelta> SubsystemStartupTimeHash;
 
 SubsystemStartupTimeHash* GetSubsystemStartupTimeHash() {
   static SubsystemStartupTimeHash* slow_startup_time_hash =
                                     new SubsystemStartupTimeHash;
   return slow_startup_time_hash;
@@ skipping 19 matching lines @@
 void SetNonBrowserUIDisplayed() {
   g_non_browser_ui_displayed = true;
 }
 
 void RecordMainEntryPointTime() {
   DCHECK(!g_main_entry_time_was_recorded);
   g_main_entry_time_was_recorded = true;
   MainEntryPointTimeInternal();
 }
 
+#if defined(OS_ANDROID)
+void RecordSavedMainEntryPointTime(const base::Time& entry_point_time) {
+  DCHECK(!g_main_entry_time_was_recorded);
+  g_main_entry_time_was_recorded = true;
+  *MainEntryPointTimeInternal() = entry_point_time;
+}
+#endif // OS_ANDROID
+
 // Return the time recorded by RecordMainEntryPointTime().
 const base::Time MainEntryStartTime() {
   DCHECK(g_main_entry_time_was_recorded);
   return *MainEntryPointTimeInternal();
 }
 
 void OnBrowserStartupComplete(bool is_first_run) {
   // Bail if uptime < 7 minutes, to filter out cases where Chrome may have been
   // autostarted and the machine is under io pressure.
   const int64 kSevenMinutesInMilliseconds =
@@ skipping 80 matching lines @@
   SubsystemStartupTimeHash* hash = GetSubsystemStartupTimeHash();
   // Only record the initial sample for a given histogram.
   if (hash->find(histogram_name_) !=  hash->end())
     return;
 
   (*hash)[histogram_name_] =
       base::TimeTicks::Now() - start_time_;
 }
 
 }  // namespace startup_metric_utils