Move remaining non-test, non-Chrome-specific Prefs code to base/prefs/.

chrome/browser/chromeos/drive/drive_system_service_browsertest.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 "chrome/browser/chromeos/drive/drive_system_service.h"
 
-#include "chrome/browser/prefs/pref_service.h"
+#include "base/prefs/pref_service.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/test/base/in_process_browser_test.h"
 
 namespace drive {
 
 class DriveSystemServiceBrowserTest : public InProcessBrowserTest {
 };
 
@@ skipping 17 matching lines @@
   // ...next try to disable drive.
   browser()->profile()->GetPrefs()->SetBoolean(prefs::kDisableDrive, true);
 
   drive_service =
       drive::DriveSystemServiceFactory::GetForProfile(browser()->profile());
 
   EXPECT_FALSE(drive_service);
 }
 
 }  // namespace drive