Move PageTransition into content namespace. While I'm touching all these files, I've also updated...

chrome/browser/tab_contents/background_contents.cc

 // Copyright (c) 2011 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/tab_contents/background_contents.h"
 
 #include "chrome/browser/background/background_contents_service.h"
 #include "chrome/browser/extensions/extension_message_service.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/renderer_preferences_util.h"
@@ skipping 64 matching lines @@
 }
 
 content::ViewType BackgroundContents::GetRenderViewType() const {
   return chrome::VIEW_TYPE_BACKGROUND_CONTENTS;
 }
 
 void BackgroundContents::DidNavigate(
     RenderViewHost* render_view_host,
     const ViewHostMsg_FrameNavigate_Params& params) {
   // We only care when the outer frame changes.
-  if (!PageTransition::IsMainFrame(params.transition))
+  if (!content::PageTransitionIsMainFrame(params.transition))
     return;
 
   // Note: because BackgroundContents are only available to extension apps,
   // navigation is limited to urls within the app's extent. This is enforced in
   // RenderView::decidePolicyForNaviation. If BackgroundContents become
   // available as a part of the web platform, it probably makes sense to have
   // some way to scope navigation of a background page to its opener's security
   // origin. Note: if the first navigation is to a URL outside the app's
   // extent a background page will be opened but will remain at about:blank.
   url_ = params.url;
@@ skipping 153 matching lines @@
 BackgroundContents*
 BackgroundContents::GetBackgroundContentsByID(int render_process_id,
                                               int render_view_id) {
   RenderViewHost* render_view_host =
       RenderViewHost::FromID(render_process_id, render_view_id);
   if (!render_view_host)
     return NULL;
 
   return render_view_host->delegate()->GetAsBackgroundContents();
 }