[Sync] Make P2PNotifier emit a notification only if some enabled types changed

chrome/browser/sync/test/integration/two_client_apps_sync_test.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 "base/basictypes.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/extensions/extension_sorting.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/sync/profile_sync_service_harness.h"
 #include "chrome/browser/sync/test/integration/apps_helper.h"
@@ skipping 277 matching lines @@
 }
 
 // TCM ID - 3718276.
 IN_PROC_BROWSER_TEST_F(TwoClientAppsSyncTest, DisableApps) {
   ASSERT_TRUE(SetupSync());
   ASSERT_TRUE(AllProfilesHaveSameAppsAsVerifier());
 
   ASSERT_TRUE(GetClient(1)->DisableSyncForDatatype(syncer::APPS));
   InstallApp(GetProfile(0), 0);
   InstallApp(verifier(), 0);
-  ASSERT_TRUE(AwaitQuiescence());
+  ASSERT_TRUE(GetClient(0)->AwaitFullSyncCompletion("Installed an app."));
   ASSERT_TRUE(HasSameAppsAsVerifier(0));
   ASSERT_FALSE(HasSameAppsAsVerifier(1));
 
   ASSERT_TRUE(GetClient(1)->EnableSyncForDatatype(syncer::APPS));
   ASSERT_TRUE(AwaitQuiescence());
 
   InstallAppsPendingForSync(GetProfile(0));
   InstallAppsPendingForSync(GetProfile(1));
   ASSERT_TRUE(AllProfilesHaveSameAppsAsVerifier());
 }
@@ skipping 93 matching lines @@
   verifier()->GetExtensionService()->extension_prefs()->
       extension_sorting()->SetPageOrdinal(extension_misc::kWebStoreAppId,
                                           cws_page_ordinal.CreateAfter());
   ASSERT_TRUE(AwaitQuiescence());
   ASSERT_TRUE(AllProfilesHaveSameAppsAsVerifier());
 }
 
 // TODO(akalin): Add tests exercising:
 //   - Offline installation/uninstallation behavior
 //   - App-specific properties