[Sync] Tidy up SyncBackendHost interface.

chrome/browser/sync/profile_sync_test_util.h

 // Copyright (c) 2010 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.
 
 #ifndef CHROME_BROWSER_SYNC_PROFILE_SYNC_TEST_UTIL_H_
 #define CHROME_BROWSER_SYNC_PROFILE_SYNC_TEST_UTIL_H_
 #pragma once
 
 #include <string>
 
@@ skipping 28 matching lines @@
   NotificationService::current()->Notify(type,
                                          NotificationService::AllSources(),
                                          NotificationService::NoDetails());
 }
 
 ACTION(QuitUIMessageLoop) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   MessageLoop::current()->Quit();
 }
 
-ACTION_P(InvokeTask, task) {
-  if (task)
-    task->Run();
-}
-
 class TestModelAssociatorHelper {
  public:
-  TestModelAssociatorHelper(browser_sync::TestIdFactory* id_factory)
+  explicit TestModelAssociatorHelper(browser_sync::TestIdFactory* id_factory)
       : id_factory_(id_factory) {
   }
 
   template <class ModelAssociatorImpl>
   bool GetSyncIdForTaggedNode(ModelAssociatorImpl* associator,
                               const std::string& tag, int64* sync_id) {
     std::wstring tag_wide;
     if (!UTF8ToWide(tag.c_str(), tag.length(), &tag_wide)) {
       NOTREACHED() << "Unable to convert UTF8 to wide for string: " << tag;
       return false;
@@ skipping 143 matching lines @@
                   const NotificationDetails& details) {
     NotificationService::current()->Notify(type, source, details);
     done_event_.Signal();
   }
 
   base::WaitableEvent done_event_;
   base::Thread* notify_thread_;
 };
 
 #endif  // CHROME_BROWSER_SYNC_PROFILE_SYNC_TEST_UTIL_H_