Revert changes to have ExtensionService notify ThemeService directly for themes

chrome/browser/themes/theme_service.cc

Index: chrome/browser/themes/theme_service.cc
diff --git a/chrome/browser/themes/theme_service.cc b/chrome/browser/themes/theme_service.cc
index 5457f1bafcaa7c287b0b40c08222dce319ef22c9..4dfe640fbaf7bbd21c836b6cce67337c09b33d2a 100644
--- a/chrome/browser/themes/theme_service.cc
+++ b/chrome/browser/themes/theme_service.cc
@@ -224,6 +224,14 @@ void ThemeService::Init(Profile* profile) {
   DCHECK(CalledOnValidThread());
   profile_ = profile;
 
+  // Listen to EXTENSION_LOADED instead of EXTENSION_INSTALLED because
+  // the extension cannot yet be found via GetExtensionById() if it is
+  // installed but not loaded (which may confuse listeners to
+  // BROWSER_THEME_CHANGED).
+  registrar_.Add(this,
+                 chrome::NOTIFICATION_EXTENSION_LOADED,
+                 content::Source<Profile>(profile_));
+
   LoadThemePrefs();
 
   theme_syncable_service_.reset(new ThemeSyncableService(profile_, this));
@@ -340,12 +348,6 @@ void ThemeService::SetTheme(const Extension* extension) {
 
   DCHECK(extension);
   DCHECK(extension->is_theme());
-  if (DCHECK_IS_ON()) {
-    ExtensionService* service =
-        extensions::ExtensionSystem::Get(profile_)->extension_service();
-    DCHECK(service);
-    DCHECK(service->GetExtensionById(extension->id(), false));
-  }
 
   BuildFromExtension(extension);
   SaveThemeID(extension->id());
@@ -654,6 +656,17 @@ void ThemeService::FreePlatformCaches() {
 }
 #endif
 
+void ThemeService::Observe(int type,
+                           const content::NotificationSource& source,
+                           const content::NotificationDetails& details) {
+  DCHECK(type == chrome::NOTIFICATION_EXTENSION_LOADED);
+  const Extension* extension = content::Details<const Extension>(details).ptr();
+  if (!extension->is_theme()) {
+    return;
+  }
+  SetTheme(extension);
+}
+
 void ThemeService::SavePackName(const FilePath& pack_path) {
   profile_->GetPrefs()->SetFilePath(
       prefs::kCurrentThemePackFilename, pack_path);