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 15 matching lines @@
 #include "components/translate/content/browser/browser_cld_utils.h"
 #include "components/translate/content/common/cld_data_source.h"
 #include "components/translate/core/browser/translate_download_manager.h"
 #include "components/variations/net/variations_http_header_provider.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/notification_types.h"
 #include "content/public/browser/power_usage_monitor.h"
+#include "content/public/browser/render_frame_host.h"
 #include "content/public/browser/site_instance.h"
 #include "content/public/common/content_client.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/common/main_function_params.h"
 #include "grit/platform_locale_settings.h"
 #include "net/base/net_module.h"
 #include "net/cookies/cookie_monster.h"
 #include "net/http/http_network_layer.h"
 #include "net/http/http_stream_factory.h"
 #include "net/url_request/url_request.h"
@@ skipping 77 matching lines @@
 
 #if defined(ENABLE_WEBRTC)
 #include "chrome/browser/media/webrtc_log_util.h"
 #endif  // defined(ENABLE_WEBRTC)
 
 #if defined(USE_AURA)
 #include "ui/aura/env.h"
 #endif  // defined(USE_AURA)
 
 using content::BrowserThread;
+using content::WebContents;
+using content::WebContentsObserver;
 
 namespace {
 
+// The basis for when tasks posted via PostAfterStartupTasks begin running.
+using StartupCompleteFlag = base::CancellationFlag;
+base::LazyInstance<StartupCompleteFlag>::Leaky g_startup_complete_flag;
+
+void SetBrowserStartupIsComplete() {
+  g_startup_complete_flag.Get().Set();

[jam, 2015/03/26 15:38:58]

what I had meant earlier (sorry if not clear), is that this would call a method
on ChromeContentBrowserClient to notify it that startup is complete. That way
CCBC doesn't need to poll.

[michaeln, 2015/03/26 19:52:33]

I've been trying to avoid providing an API to listen for the exact moment
startup completes to avoid having a bunch of stuff initiated at the same time.
Having a call into the CCBC here would continue to avoid that kind of API. OK.

I'm also trying to stick to the guidance provided here...

#if defined(CONTENT_IMPLEMENTATION)
// Content's embedder API should only be used by content.
ContentClient* GetContentClient();
#endif

... which makes it tricky to get a ptr to the CCBC and discourages doing that.

Right now (afaict), chrome/ doesn't call the CCBC instance directly anywhere,
but there are two places a static method is used.

How about I add a static CCBC method and call it here. And setup a global
instance ptr inside chrome_content_browser_client.cc so that static method can
find the instance?

[jam, 2015/03/26 20:22:08]

Why doesn't CCBC forward the tasks it gets to a file that has the startup code
that you're adding? i.e. take as much logic out of CCBC, which is already too
big.

[michaeln, 2015/03/26 21:39:36]

I guess I was trying to avoid the addition of a new class and .h .cc files. I'll
have this class and the CCBC utilize a new class and put this startup monitoring
code and the task posting code in there.

+}
+
+// Observes the first page load and set the startup complete flag accordingly.
+class StartupObserver : public WebContentsObserver {
+ public:
+  StartupObserver() : weak_factory_(this) {}
+  ~StartupObserver() override { DCHECK(IsBrowserStartupComplete()); }
+
+  void Start();
+
+ private:
+  void OnStartupComplete() {
+    SetBrowserStartupIsComplete();
+    delete this;
+  }
+
+  void OnFailsafeTimeout() { OnStartupComplete(); }
+
+  // WebContentsObserver overrides
+  void DidFinishLoad(content::RenderFrameHost* render_frame_host,
+                     const GURL& validated_url) override {
+    if (!render_frame_host->GetParent())
+      OnStartupComplete();
+  }
+
+  void DidFailLoad(content::RenderFrameHost* render_frame_host,
+                   const GURL& validated_url,
+                   int error_code,
+                   const base::string16& error_description) override {
+    if (!render_frame_host->GetParent())
+      OnStartupComplete();
+  }
+
+  void WebContentsDestroyed() override { OnStartupComplete(); }
+
+  base::WeakPtrFactory<StartupObserver> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(StartupObserver);
+};
+
+void StartupObserver::Start() {
+  // Signal completion quickly when there is no first page to load.
+  const int kShortDelaySecs = 3;
+  base::TimeDelta delay = base::TimeDelta::FromSeconds(kShortDelaySecs);
+
+#if !defined(OS_ANDROID)
+  WebContents* contents = nullptr;
+  for (chrome::BrowserIterator iter; !iter.done(); iter.Next()) {
+    contents = (*iter)->tab_strip_model()->GetActiveWebContents();
+    if (contents)
+      break;
+  }
+
+  if (contents) {
+    // Give the page time to finish loading.
+    const int kLongerDelayMins = 3;
+    Observe(contents);
+    delay = base::TimeDelta::FromMinutes(kLongerDelayMins);
+  }
+#endif  // !defined(OS_ANDROID)
+
+  BrowserThread::PostDelayedTask(
+      BrowserThread::UI, FROM_HERE,
+      base::Bind(&StartupObserver::OnFailsafeTimeout,
+                 weak_factory_.GetWeakPtr()),
+      delay);
+}
+
 // 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 346 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)
+
+  // The observer is self-deleting.
+  (new 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();
+}