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

chrome/browser/sidebar/sidebar_container.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/sidebar/sidebar_container.h"
 
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/app_modal_dialogs/message_box_handler.h"
 #include "chrome/common/extensions/extension.h"
@@ skipping 72 matching lines @@
 }
 
 void SidebarContainer::Collapse() {
   delegate_->UpdateSidebar(this);
 }
 
 void SidebarContainer::Navigate(const GURL& url) {
   // TODO(alekseys): add a progress UI.
   navigate_to_default_page_on_expand_ = false;
   sidebar_contents_->controller().LoadURL(
-      url, GURL(), PageTransition::START_PAGE, std::string());
+      url, GURL(), content::PAGE_TRANSITION_START_PAGE, std::string());
 }
 
 void SidebarContainer::SetBadgeText(const string16& badge_text) {
   badge_text_ = badge_text;
 }
 
 void SidebarContainer::SetIcon(const SkBitmap& bitmap) {
   use_default_icon_ = false;
   *icon_ = bitmap;
 }
@@ skipping 22 matching lines @@
 
 const Extension* SidebarContainer::GetExtension() const {
   Profile* profile =
       Profile::FromBrowserContext(sidebar_contents_->browser_context());
   ExtensionService* service = profile->GetExtensionService();
   if (!service)
     return NULL;
   return service->GetExtensionById(
       extension_sidebar_utils::GetExtensionIdByContentId(content_id_), false);
 }