[App Shell] Add dev tools for debugging

apps/shell/browser/shell_browser_main_parts.h

Index: apps/shell/browser/shell_browser_main_parts.h
diff --git a/apps/shell/browser/shell_browser_main_parts.h b/apps/shell/browser/shell_browser_main_parts.h
index 478514f95c7440a0afae6353a3088c74e9cf7fcb..3a97ba7233b74fe7d308b6942751781647c05097 100644
--- a/apps/shell/browser/shell_browser_main_parts.h
+++ b/apps/shell/browser/shell_browser_main_parts.h
@@ -17,6 +17,7 @@ class TestScreen;
 
 namespace content {
 class ShellBrowserContext;
+class ShellDevToolsDelegate;
 struct MainFunctionParams;
 }
 
@@ -98,6 +99,8 @@ class ShellBrowserMainParts : public content::BrowserMainParts,
 
   scoped_ptr<views::Widget> webview_window_;
 
+  scoped_ptr<content::ShellDevToolsDelegate> devtools_delegate_;
+
   // Owned by the BrowserContextKeyedService system.
   extensions::ShellExtensionSystem* extension_system_;