Create renderers for ExtensionHosts one a time to avoid blocking the UI.

chrome/browser/extensions/extension_host.h

 // Copyright (c) 2006-2009 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_
 
 #include <string>
 
 #include "base/scoped_ptr.h"
@@ skipping 20 matching lines @@
 
 // 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.
 class ExtensionHost : public RenderViewHostDelegate,
                       public RenderViewHostDelegate::View,
                       public ExtensionFunctionDispatcher::Delegate,
                       public NotificationObserver {
  public:
+  class ProcessCreationQueue;
+
   // Enable DOM automation in created render view hosts.
   static void EnableDOMAutomation() { enable_dom_automation_ = true; }
 
   ExtensionHost(Extension* extension, SiteInstance* site_instance,
                 const GURL& url, ViewType::Type host_type);
   ~ExtensionHost();
 
 #if defined(TOOLKIT_VIEWS)
   void set_view(ExtensionView* view) { view_.reset(view); }
   ExtensionView* view() const { return view_.get(); }
@@ skipping 17 matching lines @@
   bool document_element_available() const {
     return document_element_available_;
   }
 
   // Sets the the ViewType of this host (e.g. mole, toolstrip).
   void SetRenderViewType(ViewType::Type type);
 
   // Returns true if the render view is initialized and didn't crash.
   bool IsRenderViewLive() const;
 
-  // Initializes our RenderViewHost by creating its RenderView and navigating
-  // to this host's url.  Uses host_view for the RenderViewHost's view (can be
-  // NULL).
-  void CreateRenderView(RenderWidgetHostView* host_view);
+  // Prepares to initializes our RenderViewHost by creating its RenderView and
+  // navigating to this host's url. Uses host_view for the RenderViewHost's view
+  // (can be NULL). This happens delayed to avoid locking the UI.
+  void CreateRenderViewSoon(RenderWidgetHostView* host_view);
 
   // Sets |url_| and navigates |render_view_host_|.
   void NavigateToURL(const GURL& url);
 
   // Insert the theme CSS for a toolstrip/mole.
   void InsertThemeCSS();
 
   // RenderViewHostDelegate implementation.
   virtual RenderViewHostDelegate::View* GetViewDelegate();
   virtual const GURL& GetURL() const { return url_; }
@@ skipping 39 matching lines @@
   virtual void HandleMouseEvent();
   virtual void HandleMouseLeave();
   virtual void UpdatePreferredWidth(int pref_width);
 
   // NotificationObserver
   virtual void Observe(NotificationType type,
                        const NotificationSource& source,
                        const NotificationDetails& details);
 
  private:
+  friend class ProcessCreationQueue;
+
   // Whether to allow DOM automation for created RenderViewHosts. This is used
   // for testing.
   static bool enable_dom_automation_;
 
+  // Actually create the RenderView for this host. See CreateRenderViewSoon.
+  void CreateRenderViewNow();
+
   // ExtensionFunctionDispatcher::Delegate
   // If this ExtensionHost has a view, this returns the Browser that view is a
   // part of.  If this is a global background page, we use the active Browser
   // instead.
   virtual Browser* GetBrowser();
   virtual ExtensionHost* GetExtensionHost() { return this; }
 
   // Returns true if we're hosting a background page.
   // This isn't valid until CreateRenderView is called.
   bool is_background_page() const { return !view(); }
@@ skipping 33 matching lines @@
   scoped_ptr<ExtensionFunctionDispatcher> extension_function_dispatcher_;
 
   // Only EXTENSION_TOOLSTRIP and EXTENSION_BACKGROUND_PAGE are used here,
   // others are not hostd by ExtensionHost.
   ViewType::Type extension_host_type_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionHost);
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_HOST_H_