Add metrics to help measure effects of installing default apps in a profile.

chrome/browser/ui/webui/ntp/new_tab_page_handler.h

 // 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.
 
 #ifndef CHROME_BROWSER_UI_WEBUI_NTP_NEW_TAB_PAGE_HANDLER_H_
 #define CHROME_BROWSER_UI_WEBUI_NTP_NEW_TAB_PAGE_HANDLER_H_
 
 #include "base/values.h"
 #include "content/browser/webui/web_ui.h"
 
 class PrefService;
 class Profile;
 
 // Handler for general New Tab Page functionality that does not belong in a
 // more specialized handler.
 class NewTabPageHandler : public WebUIMessageHandler {
  public:
   NewTabPageHandler() {}
   virtual ~NewTabPageHandler() {}
 
   // WebUIMessageHandler implementation.
+  virtual WebUIMessageHandler* Attach(WebUI* web_ui) OVERRIDE;
   virtual void RegisterMessages() OVERRIDE;
 
   // Callback for "closePromo".
   void HandleClosePromo(const ListValue* args);
 
   // Callback for "pageSelected".
   void HandlePageSelected(const ListValue* args);
 
   // Callback for "introMessageDismissed". This is called when the close button
   // on the ntp4 bubble is clicked or when a NavDot is clicked.
@@ skipping 11 matching lines @@
 
   // Permanently dismiss the ntp4 bubble for new users.
   static void DismissIntroMessage(PrefService* prefs);
 
  private:
   // The purpose of this enum is to track which page on the NTP is showing.
   // The lower 10 bits of kNTPShownPage are used for the index within the page
   // group, and the rest of the bits are used for the page group ID (defined
   // here).
   enum {
-    INDEX_MASK = (1 << 10) - 1,
-    MOST_VISITED_PAGE_ID = 1 << 10,
-    APPS_PAGE_ID = 2 << 10,
-    BOOKMARKS_PAGE_ID = 3 << 10,
+    PAGE_ID_OFFSET = 10,
+    INDEX_MASK = (1 << PAGE_ID_OFFSET) - 1,
+    MOST_VISITED_PAGE_ID = 1 << PAGE_ID_OFFSET,
+    APPS_PAGE_ID = 2 << PAGE_ID_OFFSET,
+    BOOKMARKS_PAGE_ID = 3 << PAGE_ID_OFFSET,
   };
 
   DISALLOW_COPY_AND_ASSIGN(NewTabPageHandler);
 };
 
 #endif  // CHROME_BROWSER_UI_WEBUI_NTP_NEW_TAB_PAGE_HANDLER_H_