avoid dereferencing NULL extension in ExtensionHost

chrome/browser/extensions/extension_host.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_EXTENSIONS_EXTENSION_HOST_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_HOST_H_
 #pragma once
 
 #include <string>
 #include <vector>
 
 #include "base/memory/scoped_ptr.h"
 #include "base/perftimer.h"
 #include "chrome/browser/extensions/extension_function_dispatcher.h"
 #include "chrome/browser/tab_contents/render_view_host_delegate_helper.h"
 #include "chrome/browser/ui/app_modal_dialogs/js_modal_dialog.h"
+#include "chrome/common/extensions/extension.h"
 #include "content/browser/renderer_host/render_view_host_delegate.h"
 #include "content/common/notification_registrar.h"
 
 #if defined(TOOLKIT_VIEWS)
 #include "chrome/browser/ui/views/extensions/extension_view.h"
 #elif defined(OS_MACOSX)
 #include "chrome/browser/ui/cocoa/extensions/extension_view_mac.h"
 #elif defined(TOOLKIT_GTK)
 #include "chrome/browser/ui/gtk/extensions/extension_view_gtk.h"
 #endif
 
 class Browser;
-class Extension;
 class FileSelectHelper;
 class RenderProcessHost;
 class RenderWidgetHostView;
 class TabContents;
 struct ViewHostMsg_RunFileChooser_Params;
 struct WebPreferences;
 
 // This class is the browser component of an extension component's RenderView.
 // It handles setting up the renderer process, if needed, with special
 // privileges available to extensions.  It may have a view to be shown in the
-// in the browser UI, or it may be hidden.
+// browser UI, or it may be hidden.
 class ExtensionHost : public RenderViewHostDelegate,
                       public RenderViewHostDelegate::View,
                       public ExtensionFunctionDispatcher::Delegate,
                       public NotificationObserver,
                       public JavaScriptAppModalDialogDelegate {
  public:
   class ProcessCreationQueue;
 
   // Enable DOM automation in created render view hosts.
   static void EnableDOMAutomation() { enable_dom_automation_ = true; }
@@ skipping 14 matching lines @@
   ExtensionViewGtk* view() { return view_.get(); }
 #endif
 
   // Create an ExtensionView and tie it to this host and |browser|.  Note NULL
   // is a valid argument for |browser|.  Extension views may be bound to
   // tab-contents hosted in ExternalTabContainer objects, which do not
   // instantiate Browser objects.
   void CreateView(Browser* browser);
 
   const Extension* extension() const { return extension_; }
+  const std::string& id() const {

[Matt Perry, 2011/05/06 18:19:36]

I think this should be named extension_id (and the member var). ID is ambiguous
in this context.

[Denis Lagno, 2011/05/06 19:50:33]

Done.

+    DCHECK(extension_ == NULL || extension_->id() == id_);

[Matt Perry, 2011/05/06 18:19:36]

nit: this is overkill IMO. I'd leave it out.

[Denis Lagno, 2011/05/06 19:50:33]

Done.

+    return id_;
+  }
   RenderViewHost* render_view_host() const { return render_view_host_; }
   RenderProcessHost* render_process_host() const;
   SiteInstance* site_instance() const;
   bool did_stop_loading() const { return did_stop_loading_; }
   bool document_element_available() const {
     return document_element_available_;
   }
 
   Profile* profile() const { return profile_; }
 
@@ skipping 149 matching lines @@
   // event in platform specific way.
   virtual void UnhandledKeyboardEvent(const NativeWebKeyboardEvent& event) {}
 
   // Returns true if we're hosting a background page.
   // This isn't valid until CreateRenderView is called.
   bool is_background_page() const { return !view(); }
 
   // The extension that we're hosting in this view.
   const Extension* extension_;
 
+  // Id of extension that we're hosting in this view.
+  std::string id_;

[akalin, 2011/05/06 18:40:31]

may as well make this const

[Denis Lagno, 2011/05/06 19:50:33]

Done.

+
   // The profile that this host is tied to.
   Profile* profile_;
 
   // Optional view that shows the rendered content in the UI.
 #if defined(TOOLKIT_VIEWS)
   scoped_ptr<ExtensionView> view_;
 #elif defined(OS_MACOSX)
   scoped_ptr<ExtensionViewMac> view_;
 #elif defined(TOOLKIT_GTK)
   scoped_ptr<ExtensionViewGtk> view_;
@@ skipping 34 matching lines @@
   // The time that the last javascript message was dismissed.
   base::TimeTicks last_javascript_message_dismissal_;
 
   // Whether to suppress all javascript messages.
   bool suppress_javascript_messages_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionHost);
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_HOST_H_