[Android] Support startup histogram.

chrome/browser/chrome_browser_main.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/browser/chrome_browser_main.h"
 
 #if defined(TOOLKIT_GTK)
 #include <gtk/gtk.h>
 #endif
 
@@ skipping 668 matching lines @@
 #endif  // defined(GOOGLE_CHROME_BUILD)
   return enabled;
 }
 
 void ChromeBrowserMainParts::RecordBrowserStartupTime() {
   // Don't record any metrics if UI was displayed before this point e.g.
   // warning dialogs.
   if (startup_metric_utils::WasNonBrowserUIDisplayed())
     return;
 
+#if defined(OS_ANDROID)
+  // On Android the first run is handled in Java code, and the C++ side of
+  // Chrome doesn't know if this is the first run. This will cause some
+  // inaccuracy in the UMA statistics, but this should be minor (first runs are
+  // rare).
+  bool is_first_run = false;
+#else
   bool is_first_run = first_run::IsChromeFirstRun();
+#endif
 
 // CurrentProcessInfo::CreationTime() is currently only implemented on some
 // platforms.
 #if defined(OS_MACOSX) || defined(OS_WIN) || defined(OS_LINUX)
   const base::Time process_creation_time =
       base::CurrentProcessInfo::CreationTime();
 
   if (!is_first_run && !process_creation_time.is_null()) {
     RecordPreReadExperimentTime("Startup.BrowserMessageLoopStartTime",
         base::Time::Now() - process_creation_time);
@@ skipping 888 matching lines @@
 
   if (parameters().ui_task) {
     // We end the startup timer here if we have parameters to run, because we
     // never start to run the main loop (where we normally stop the timer).
     startup_timer_->SignalStartupComplete(
         performance_monitor::StartupTimer::STARTUP_TEST);
     parameters().ui_task->Run();
     delete parameters().ui_task;
     run_message_loop_ = false;
   }
-
+#if defined(OS_ANDROID)
+  // We never run the C++ main loop on Android, since the UI thread message
+  // loop is controlled by the OS, so this is as close as we can get to
+  // the start of the main loop
+  if (result_code_ <= 0) {
+    RecordBrowserStartupTime();
+  }
+#endif
   return result_code_;
 }
 
 bool ChromeBrowserMainParts::MainMessageLoopRun(int* result_code) {
   TRACE_EVENT0("startup", "ChromeBrowserMainParts::MainMessageLoopRun");
 #if defined(OS_ANDROID)
   // Chrome on Android does not use default MessageLoop. It has its own
   // Android specific MessageLoop
   NOTREACHED();
   return true;
@@ skipping 91 matching lines @@
   chromeos::CrosSettings::Shutdown();
 #endif
 #endif
 }
 
 // Public members:
 
 void ChromeBrowserMainParts::AddParts(ChromeBrowserMainExtraParts* parts) {
   chrome_extra_parts_.push_back(parts);
 }