Implements AddStartupEventsForTelemetry() in startup_metric_utils.cc for in-coming startup telemetry

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"
 
 #include <set>
 #include <string>
 #include <vector>
 
@@ skipping 1636 matching lines @@
     // will be initialized when the app enters foreground mode.
     variations_service->set_policy_pref_service(profile_->GetPrefs());
   }
   translate::TranslateDownloadManager::RequestLanguageList(
       profile_->GetPrefs());
 
 #else
   // Most general initialization is behind us, but opening a
   // tab and/or session restore and such is still to be done.
   base::TimeTicks browser_open_start = base::TimeTicks::Now();
+  TRACE_EVENT_BEGIN0("startup", "Startup.BrowserOpenTabs");
 
   // We are in regular browser boot sequence. Open initial tabs and enter the
   // main message loop.
   std::vector<Profile*> last_opened_profiles;
 #if !defined(OS_CHROMEOS)
   // On ChromeOS multiple profiles doesn't apply, and will break if we load
   // them this early as the cryptohome hasn't yet been mounted (which happens
   // only once we log in).
   last_opened_profiles =
       g_browser_process->profile_manager()->GetLastOpenedProfiles();
@@ skipping 30 matching lines @@
 #if defined(OS_MACOSX)
     // Call Recycle() here as late as possible, before going into the loop
     // because Start() will add things to it while creating the main window.
     if (parameters().autorelease_pool)
       parameters().autorelease_pool->Recycle();
 #endif  // defined(OS_MACOSX)
 
     const base::TimeDelta delta = base::TimeTicks::Now() - browser_open_start;
     startup_metric_utils::RecordBrowserOpenTabsDelta(delta);
 
+    TRACE_EVENT_END0("startup", "Startup.BrowserOpenTabs");

[gab, 2015/11/10 19:30:53]

I like these, except I'm not convinced they belong in this specific change?
Perhaps split it into multiple dedicated CLs?

[gabadie, 2015/11/12 08:57:20]

Done.

+
     // If we're running tests (ui_task is non-null), then we don't want to
     // call RequestLanguageList or StartRepeatedVariationsSeedFetch or
     // RequestLanguageList
     if (parameters().ui_task == NULL) {
       // Request new variations seed information from server.
       variations::VariationsService* variations_service =
           browser_process_->variations_service();
       if (variations_service)
         variations_service->PerformPreMainMessageLoopStartup();
 
@@ skipping 145 matching lines @@
   chromeos::CrosSettings::Shutdown();
 #endif  // defined(OS_CHROMEOS)
 #endif  // defined(OS_ANDROID)
 }
 
 // Public members:
 
 void ChromeBrowserMainParts::AddParts(ChromeBrowserMainExtraParts* parts) {
   chrome_extra_parts_.push_back(parts);
 }