[Cleanup] Factor out common code.

chrome/browser/ui/chrome_pages.h

 // 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.
 
 #ifndef CHROME_BROWSER_UI_CHROME_PAGES_H_
 #define CHROME_BROWSER_UI_CHROME_PAGES_H_
 
 #include <stdint.h>
 
 #include <string>
@@ skipping 19 matching lines @@
   // Keyboard accelerators.
   HELP_SOURCE_KEYBOARD,
 
   // Menus (e.g. app menu or Chrome OS system menu).
   HELP_SOURCE_MENU,
 
   // WebUI (the "About" page).
   HELP_SOURCE_WEBUI,
 };
 
+// Determine if a |url| points to an internal page.
+bool IsInternalPage(const GURL& url);

[sky, 2016/06/02 21:46:39]

'Internal' is confusing here. Why isn't chrome://omnibox considered 'internal'? 

 
 void ShowBookmarkManager(Browser* browser);
 void ShowBookmarkManagerForNode(Browser* browser, int64_t node_id);
 void ShowHistory(Browser* browser);
 void ShowDownloads(Browser* browser);
 void ShowExtensions(Browser* browser,
                     const std::string& extension_to_highlight);
 void ShowConflicts(Browser* browser);
 
 // ShowFeedbackPage() uses |browser| to determine the URL of the current tab.
@@ skipping 46 matching lines @@
 
 // If the user is already signed in, shows the "Signin" portion of Settings,
 // otherwise initiates signin in a new browser tab.
 void ShowBrowserSigninOrSettings(Browser* browser,
                                  signin_metrics::AccessPoint access_point);
 #endif
 
 }  // namespace chrome
 
 #endif  // CHROME_BROWSER_UI_CHROME_PAGES_H_