Make clicking the restart bubble for crashed apps work.

Previously AppLoadService listened for
NOTIFICATION_EXTENSION_HOST_DID_STOP_LOADING before dispatching the
onRestarted() event after a reload, but in the case of packaged apps, which use
non-persistent background pages, that notification will never get fired. This
is because reloading an app doesn't cause its background page to get loaded -
only a relevant event causes the page to be woken up.

This patch fixes the issue by listening for NOTIFICATION_EXTENSION_LOADED
instead, which is always fired after a reload. It also determines whether an
extension is listening to an event by checking which events it has registered
for, not which ones it currently has a listener for,
NOTIFICATION_EXTENSION_LOADED is the notification that listeners get created
on, and so to avoid raciness we check registered events (ie: the persisted
list of events that an extension is interested in).

BUG=327964

Review URL: https://codereview.chromium.org/93593003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@241162 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 11 insertions, 14 deletions

diff --git a/apps/app_load_service.cc b/apps/app_load_service.cc
index 496b4da..ecf0636 100644
--- a/apps/app_load_service.cc
+++ b/apps/app_load_service.cc
@@ -33,7 +33,7 @@ AppLoadService::PostReloadAction::PostReloadAction()
 AppLoadService::AppLoadService(Profile* profile)
     : profile_(profile) {
   registrar_.Add(
-      this, chrome::NOTIFICATION_EXTENSION_HOST_DID_STOP_LOADING,
+      this, chrome::NOTIFICATION_EXTENSION_LOADED,
       content::NotificationService::AllSources());
   registrar_.Add(
       this, chrome::NOTIFICATION_EXTENSION_UNLOADED,
@@ -78,13 +78,8 @@ void AppLoadService::Observe(int type,
                              const content::NotificationSource& source,
                              const content::NotificationDetails& details) {
   switch (type) {
-    case chrome::NOTIFICATION_EXTENSION_HOST_DID_STOP_LOADING: {
-      extensions::ExtensionHost* host =
-          content::Details<extensions::ExtensionHost>(details).ptr();
-      const Extension* extension = host->extension();
-      // It is possible for an extension to be unloaded before it stops loading.
-      if (!extension)
-        break;
+    case chrome::NOTIFICATION_EXTENSION_LOADED: {
+      Extension* extension = content::Details<Extension>(details).ptr();
       std::map<std::string, PostReloadAction>::iterator it =
           post_reload_actions_.find(extension->id());
       if (it == post_reload_actions_.end())
diff --git a/apps/launcher.cc b/apps/launcher.cc
index 6b077dd..4f79973 100644
--- a/apps/launcher.cc
+++ b/apps/launcher.cc
@@ -380,9 +380,12 @@ void RestartPlatformApp(Profile* profile, const Extension* extension) {
 #endif
   extensions::EventRouter* event_router =
       ExtensionSystem::Get(profile)->event_router();
-  bool listening_to_restart = event_router->
-      ExtensionHasEventListener(extension->id(),
-                                app_runtime::OnRestarted::kEventName);
+  // We check for registered events, rather than listeners, because listeners
+  // may not be instantiated for the events yet.
+  std::set<std::string> events =
+      event_router->GetRegisteredEvents(extension->id());
+  bool listening_to_restart =
+      events.count(app_runtime::OnRestarted::kEventName) > 0;
 
   if (listening_to_restart) {
     extensions::AppEventRouter::DispatchOnRestartedEvent(profile, extension);
@@ -393,9 +396,8 @@ void RestartPlatformApp(Profile* profile, const Extension* extension) {
       extension_service()->extension_prefs();
   bool had_windows = extension_prefs->IsActive(extension->id());
   extension_prefs->SetIsActive(extension->id(), false);
-  bool listening_to_launch = event_router->
-      ExtensionHasEventListener(extension->id(),
-                                app_runtime::OnLaunched::kEventName);
+  bool listening_to_launch =
+      events.count(app_runtime::OnLaunched::kEventName) > 0;
 
   if (listening_to_launch && had_windows)
     LaunchPlatformAppWithNoData(profile, extension);