Unpack theme data from extensions off of UI thread.

chrome/browser/extensions/extension_service_sync_unittest.cc

Index: chrome/browser/extensions/extension_service_sync_unittest.cc
diff --git a/chrome/browser/extensions/extension_service_sync_unittest.cc b/chrome/browser/extensions/extension_service_sync_unittest.cc
index 1b810fa91a142b85b2d532312fa24bc3fa3cfcb9..8d91faa87b5eb1c7562a79d2734f2967b68abf3c 100644
--- a/chrome/browser/extensions/extension_service_sync_unittest.cc
+++ b/chrome/browser/extensions/extension_service_sync_unittest.cc
@@ -18,6 +18,7 @@
 #include "base/metrics/field_trial.h"
 #include "base/test/mock_entropy_provider.h"
 #include "base/test/scoped_feature_list.h"
+#include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/extensions/api/webstore_private/webstore_private_api.h"
 #include "chrome/browser/extensions/component_loader.h"
 #include "chrome/browser/extensions/extension_service.h"
@@ -28,6 +29,8 @@
 #include "chrome/browser/extensions/scripting_permissions_modifier.h"
 #include "chrome/browser/extensions/updater/extension_updater.h"
 #include "chrome/browser/sync/profile_sync_service_factory.h"
+#include "chrome/browser/themes/theme_service.h"
+#include "chrome/browser/themes/theme_service_factory.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/extensions/sync_helper.h"
@@ -1563,6 +1566,11 @@ TEST_F(ExtensionServiceSyncTest, DontSyncThemes) {
   // Installing a theme should not result in a sync change (themes are handled
   // separately by ThemeSyncableService).
   InstallCRX(data_dir().AppendASCII("theme.crx"), INSTALL_NEW);
+  content::WindowedNotificationObserver theme_change_observer(
+      chrome::NOTIFICATION_BROWSER_THEME_CHANGED,
+      content::Source<ThemeService>(
+          ThemeServiceFactory::GetForProfile(profile())));
+  theme_change_observer.Wait();
   EXPECT_TRUE(processor->changes().empty());
 }