Introduce ChromeZoomLevelPref, make zoom level prefs independent of profile prefs.

chrome/browser/ui/zoom/zoom_controller_browsertest.cc

 // Copyright 2014 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/ui/zoom/zoom_controller.h"
 
 #include "base/prefs/pref_service.h"
 #include "base/process/kill.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser.h"
@@ skipping 87 matching lines @@
   // zoom level will change the zoom level for this web_contents.
   ZoomController::ZoomChangedEventData zoom_change_data(
       web_contents,
       new_default_zoom_level,
       new_default_zoom_level,
       ZoomController::ZOOM_MODE_DEFAULT,
       true);
   ZoomChangedWatcher zoom_change_watcher(web_contents, zoom_change_data);
   // TODO(wjmaclean): Convert this to call partition-specific zoom level prefs
   // when they become available.
-  browser()->profile()->GetPrefs()->SetDouble(prefs::kDefaultZoomLevel,
-                                              new_default_zoom_level);
+  browser()->profile()->GetZoomLevelPrefs()->SetDouble(prefs::kDefaultZoomLevel,
+                                                       new_default_zoom_level);
   // Because this test relies on a round-trip IPC to/from the renderer process,
   // we need to wait for it to propagate.
   zoom_change_watcher.Wait();
 }