Add a menu item to content_shell to open devtools to make it more discoverable.

content/shell/shell.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 CONTENT_SHELL_SHELL_H_
 #define CONTENT_SHELL_SHELL_H_
 
 
 #include <vector>
 
@@ skipping 40 matching lines @@
               public NotificationObserver {
  public:
   virtual ~Shell();
 
   void LoadURL(const GURL& url);
   void GoBackOrForward(int offset);
   void Reload();
   void Stop();
   void UpdateNavigationControls();
   void Close();
+  void ShowDevTools();
 
   // Do one time initialization at application startup.
   static void PlatformInitialize();
 
   // This is called indirectly by the modules that need access resources.
   static base::StringPiece PlatformResourceProvider(int key);
 
   static Shell* CreateNewWindow(BrowserContext* browser_context,
                                 const GURL& url,
                                 SiteInstance* site_instance,
@@ skipping 157 matching lines @@
   static base::Callback<void(Shell*)> shell_created_callback_;
 
   // True if the destructur of Shell should post a quit closure on the current
   // message loop if the destructed Shell object was the last one.
   static bool quit_message_loop_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_SHELL_SHELL_H_