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 13 matching lines @@
 #include "base/prefs/pref_value_store.h"
 #include "base/prefs/scoped_user_pref_update.h"
 #include "base/process/process_info.h"
 #include "base/profiler/scoped_tracker.h"
 #include "base/run_loop.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_piece.h"
 #include "base/strings/string_split.h"
 #include "base/strings/sys_string_conversions.h"
 #include "base/strings/utf_string_conversions.h"
+#include "base/synchronization/cancellation_flag.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/browser_process.h"
 #include "chrome/browser/browser_process_impl.h"
@@ skipping 34 matching lines @@
 #include "chrome/browser/printing/cloud_print/cloud_print_proxy_service_factory.h"
 #include "chrome/browser/process_singleton.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/profiles/profile_manager.h"
 #include "chrome/browser/profiles/profiles_state.h"
 #include "chrome/browser/shell_integration.h"
 #include "chrome/browser/translate/translate_service.h"
 #include "chrome/browser/ui/app_list/app_list_service.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_finder.h"
+#include "chrome/browser/ui/browser_iterator.h"
 #include "chrome/browser/ui/host_desktop.h"
 #include "chrome/browser/ui/startup/bad_flags_prompt.h"
 #include "chrome/browser/ui/startup/default_browser_prompt.h"
 #include "chrome/browser/ui/startup/startup_browser_creator.h"
+#include "chrome/browser/ui/tabs/tab_strip_model.h"
 #include "chrome/browser/ui/uma_browsing_activity_observer.h"
 #include "chrome/browser/ui/webui/chrome_web_ui_controller_factory.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/chrome_paths.h"
 #include "chrome/common/chrome_result_codes.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/chrome_version_info.h"
 #include "chrome/common/crash_keys.h"
 #include "chrome/common/env_vars.h"
 #include "chrome/common/logging_chrome.h"
@@ skipping 115 matching lines @@
 #endif  // defined(ENABLE_WEBRTC)
 
 #if defined(USE_AURA)
 #include "ui/aura/env.h"
 #endif  // defined(USE_AURA)
 
 using content::BrowserThread;
 
 namespace {
 
+using StartupCompleteFlag = base::CancellationFlag;
+base::LazyInstance<StartupCompleteFlag>::Leaky g_startup_complete_flag;
+
+// Used to monitor the first page load to inform PostAfterStartupTask.
+class StartupObserver : public content::WebContentsObserver {
+ public:
+  static void Start();
+
+ private:
+  static content::WebContents* GetFirstWebContents();
+  static void SetBrowserStartupIsComplete();

[michaeln, 2015/03/20 00:21:28]

i'll probably have to expose SetBrowserStartupIsComplete for testing

+
+  explicit StartupObserver(content::WebContents* web_contents)
+      : content::WebContentsObserver(web_contents) {}
+
+  // WebContentsObserver overrides
+  void DidFinishLoad(content::RenderFrameHost* render_frame_host,
+                     const GURL& validated_url) override;
+  void DidFailLoad(content::RenderFrameHost* render_frame_host,
+                   const GURL& validated_url,
+                   int error_code,
+                   const base::string16& error_description) override;
+  void WebContentsDestroyed() override;
+};
+
+void StartupObserver::Start() {
+  // Signal completion quickly when there is no first page to load.
+  int kDefaultDelaySecs = 3;
+  base::TimeDelta delay = base::TimeDelta::FromSeconds(kDefaultDelaySecs);
+
+#if !defined(OS_ANDROID)
+  content::WebContents* web_contents = GetFirstWebContents();
+  if (web_contents) {
+    // StartupObserver is self deleting.
+    new StartupObserver(web_contents);
+
+    // In case startup oberver never signals completion.
+    const int kFailsafeDelayMins = 3;
+    delay = base::TimeDelta::FromMinutes(kFailsafeDelayMins);
+  }
+#endif  // !defined(OS_ANDROID)
+
+  BrowserThread::PostDelayedTask(BrowserThread::UI, FROM_HERE,
+                                 base::Bind(&SetBrowserStartupIsComplete),
+                                 delay);
+}
+
+content::WebContents* StartupObserver::GetFirstWebContents() {
+  for (chrome::BrowserIterator iterator; !iterator.done(); iterator.Next()) {
+    Browser* browser = *iterator;
+    content::WebContents* web_contents =
+        browser->tab_strip_model()->GetActiveWebContents();
+    if (web_contents)
+      return web_contents;
+  }
+  return nullptr;
+}
+
+void StartupObserver::SetBrowserStartupIsComplete() {
+  g_startup_complete_flag.Get().Set();
+}
+
+void StartupObserver::DidFinishLoad(content::RenderFrameHost* render_frame_host,
+                                    const GURL& validated_url) {
+  SetBrowserStartupIsComplete();
+  delete this;
+}
+
+void StartupObserver::DidFailLoad(content::RenderFrameHost* render_frame_host,
+                                  const GURL& validated_url,
+                                  int error_code,
+                                  const base::string16& error_description) {
+  SetBrowserStartupIsComplete();
+  delete this;
+}
+
+void StartupObserver::WebContentsDestroyed() {
+  SetBrowserStartupIsComplete();
+  delete this;
+}
+
 // This function provides some ways to test crash and assertion handling
 // behavior of the program.
 void HandleTestParameters(const base::CommandLine& command_line) {
   // This parameter causes a null pointer crash (crash reporter trigger).
   if (command_line.HasSwitch(switches::kBrowserCrashTest)) {
     int* bad_pointer = NULL;
     *bad_pointer = 0;
   }
 }
 
@@ skipping 344 matching lines @@
       local_state_(NULL),
       restart_last_session_(false) {
   // If we're running tests (ui_task is non-null).
   if (parameters.ui_task)
     browser_defaults::enable_help_app = false;
 
   // Chrome disallows cookies by default. All code paths that want to use
   // cookies need to go through one of Chrome's URLRequestContexts which have
   // a ChromeNetworkDelegate attached that selectively allows cookies again.
   net::URLRequest::SetDefaultCookiePolicyToBlock();
+
+  // Be sure to allocate the lazy instance on the main thread.
+  g_startup_complete_flag.Get();
 }
 
 ChromeBrowserMainParts::~ChromeBrowserMainParts() {
   for (int i = static_cast<int>(chrome_extra_parts_.size())-1; i >= 0; --i)
     delete chrome_extra_parts_[i];
   chrome_extra_parts_.clear();
 }
 
 // This will be called after the command-line has been mutated by about:flags
 void ChromeBrowserMainParts::SetupMetricsAndFieldTrials() {
@@ skipping 501 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)
+  StartupObserver::Start();
 }
 
 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);
 }
+
+bool IsBrowserStartupComplete() {
+  return g_startup_complete_flag.Get().IsSet();
+}