Add a non-blocking "OneShotEvent" class

chrome/browser/extensions/extension_service.cc

Index: chrome/browser/extensions/extension_service.cc
diff --git a/chrome/browser/extensions/extension_service.cc b/chrome/browser/extensions/extension_service.cc
index 2cfc14495d5feff32ae24d9208049e49ab16d2bc..b4bfde998af0ab8f78bf2f361192d6436859fb82 100644
--- a/chrome/browser/extensions/extension_service.cc
+++ b/chrome/browser/extensions/extension_service.cc
@@ -350,7 +350,6 @@ ExtensionService::ExtensionService(Profile* profile,
       extensions_enabled_(extensions_enabled),
       show_extensions_prompts_(true),
       install_updates_when_idle_(true),
-      ready_(false),
       toolbar_model_(this),
       menu_manager_(profile),
       event_routers_initialized_(false),
@@ -562,7 +561,7 @@ const Extension* ExtensionService::GetExtensionById(
 void ExtensionService::Init() {
   CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
-  DCHECK(!ready_);  // Can't redo init.
+  DCHECK(!ready_.has_happened());  // Can't redo init.
   DCHECK_EQ(extensions_.size(), 0u);
 
   const CommandLine* cmd_line = CommandLine::ForCurrentProcess();
@@ -585,12 +584,13 @@ void ExtensionService::Init() {
       // import process.
 
       extensions::InstalledLoader(this).LoadAllExtensions();
+      SetReadyAndNotifyListeners();
       RegisterForImportFinished();
     } else {
-      // In this case, LoadAllExtensions() calls OnLoadedInstalledExtensions(),
-      // which calls SetReadyAndNotifyListeners().
+      // In this case, LoadAllExtensions() calls OnLoadedInstalledExtensions().
       component_loader_->LoadAll();
       extensions::InstalledLoader(this).LoadAllExtensions();
+      SetReadyAndNotifyListeners();
 
       // TODO(erikkay) this should probably be deferred to a future point
       // rather than running immediately at startup.
@@ -1234,10 +1234,6 @@ extensions::ContentSettingsStore* ExtensionService::GetContentSettingsStore() {
   return extension_prefs()->content_settings_store();
 }
 
-bool ExtensionService::is_ready() {
-  return ready_;
-}
-
 base::SequencedTaskRunner* ExtensionService::GetFileTaskRunner() {
   if (file_task_runner_)
     return file_task_runner_;
@@ -1959,6 +1955,8 @@ void ExtensionService::ReloadExtensions() {
   UnloadAllExtensions();
   component_loader_->LoadAll();
   extensions::InstalledLoader(this).LoadAllExtensions();
+  // Don't call SetReadyAndNotifyListeners() since tests call this multiple
+  // times.
 }
 
 void ExtensionService::GarbageCollectExtensions() {
@@ -2017,7 +2015,7 @@ void ExtensionService::SyncExtensionChangeIfNeeded(const Extension& extension) {
 }
 
 void ExtensionService::SetReadyAndNotifyListeners() {
-  ready_ = true;
+  ready_.MarkHappened();
   content::NotificationService::current()->Notify(
       chrome::NOTIFICATION_EXTENSIONS_READY,
       content::Source<Profile>(profile_),
@@ -2029,8 +2027,6 @@ void ExtensionService::OnLoadedInstalledExtensions() {
     updater_->Start();
 
   OnBlacklistUpdated();
-
-  SetReadyAndNotifyListeners();
 }
 
 void ExtensionService::AddExtension(const Extension* extension) {