Implement a poor man's PostAfterStartupTask() function.

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 21 matching lines @@
 #include "base/strings/sys_string_conversions.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/sys_info.h"
 #include "base/threading/platform_thread.h"
 #include "base/time/time.h"
 #include "base/trace_event/trace_event.h"
 #include "base/values.h"
 #include "build/build_config.h"
 #include "cc/base/switches.h"
 #include "chrome/browser/about_flags.h"
+#include "chrome/browser/after_startup_task.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/browser_process_impl.h"
 #include "chrome/browser/browser_process_platform_part.h"
 #include "chrome/browser/browser_shutdown.h"
 #include "chrome/browser/chrome_browser_main_extra_parts.h"
 #include "chrome/browser/component_updater/cld_component_installer.h"
 #include "chrome/browser/component_updater/ev_whitelist_component_installer.h"
 #include "chrome/browser/component_updater/flash_component_installer.h"
 #include "chrome/browser/component_updater/recovery_component_installer.h"
 #include "chrome/browser/component_updater/supervised_user_whitelist_installer.h"
@@ skipping 1052 matching lines @@
 #endif  // !defined(OS_ANDROID)
 #if defined(ENABLE_WEBRTC)
   // Set up a task to delete old WebRTC log files for all profiles. Use a delay
   // to reduce the impact on startup time.
   BrowserThread::PostDelayedTask(
       BrowserThread::UI,
       FROM_HERE,
       base::Bind(&WebRtcLogUtil::DeleteOldWebRtcLogFilesForAllProfiles),
       base::TimeDelta::FromMinutes(1));
 #endif  // defined(ENABLE_WEBRTC)
+
+  StartMonitoringStartup();

[gab, 2015/03/30 18:29:37]

Add a comment why this is the right spot for this.

(i.e. browser was started and we can thus tell whether we should be waiting for
something to paint, but nothing can actually have painted yet as the main
message loop hasn't started so begin observation now...)

[michaeln, 2015/04/03 19:51:38]

Done.

 }
 
 int ChromeBrowserMainParts::PreMainMessageLoopRunImpl() {
   TRACE_EVENT0("startup", "ChromeBrowserMainParts::PreMainMessageLoopRunImpl");
   SCOPED_UMA_HISTOGRAM_LONG_TIMER("Startup.PreMainMessageLoopRunImplLongTime");
   const base::TimeTicks start_time_step1 = base::TimeTicks::Now();
   // Android updates the metrics service dynamically depending on whether the
   // application is in the foreground or not. Do not start here.
 #if !defined(OS_ANDROID)
   // Now that the file thread has been started, start recording.
@@ skipping 606 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);
 }