Don't load plugins on prerendered pages until the pages are displayed....

chrome/renderer/blocked_plugin.h

 // Copyright (c) 2010 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_RENDERER_BLOCKED_PLUGIN_H_
 #define CHROME_RENDERER_BLOCKED_PLUGIN_H_
 #pragma once
 
 #include "chrome/renderer/render_view_observer.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebPluginParams.h"
@@ skipping 11 matching lines @@
 class BlockedPlugin : public RenderViewObserver,
                       public CppBoundClass,
                       public webkit::npapi::WebViewPlugin::Delegate {
  public:
   BlockedPlugin(RenderView* render_view,
                 WebKit::WebFrame* frame,
                 const webkit::npapi::PluginGroup& info,
                 const WebKit::WebPluginParams& params,
                 const WebPreferences& settings,
                 int template_id,
-                const string16& message);
+                const string16& message,
+                bool is_blocked_for_prerendering);

[cbentzel, 2011/01/20 19:46:59]

Would it make sense to use an enum like BLOCKED_REASON_PRERENDER and
BLOCKED_REASON_CLICKTOPLAY rather than have a naked bool? 

[mmenke, 2011/01/20 20:04:22]

It might.  Seems we have 4 reasons, I believe - outdated plugin, click to play,
"blocked" (No idea about that one), and prerendering.  The only difference in
behavior for the other 3 are the values of |template_id| and |message|, which
are currently parameters passed to the BlockedPlugin.

It might make sense to assign those strings in BlockedPlugin based on an enum,
rather than in RenderView.  I think it's tangential enough a change to not
really belong in this CL, and I have no idea what the 3rd reason actually means.

 
   webkit::npapi::WebViewPlugin* plugin() { return plugin_; }
 
   // WebViewPlugin::Delegate methods:
   virtual void BindWebFrame(WebKit::WebFrame* frame);
   virtual void WillDestroyPlugin();
   virtual void ShowContextMenu(const WebKit::WebMouseEvent&);
 
  private:
   virtual ~BlockedPlugin();
@@ skipping 18 matching lines @@
   // Hide the blocked plugin.
   void HidePlugin();
 
   WebKit::WebFrame* frame_;
   WebKit::WebPluginParams plugin_params_;
   webkit::npapi::WebViewPlugin* plugin_;
   // The name of the plugin that was blocked.
   string16 name_;
   // True iff we're showing a custom menu.
   bool custom_menu_showing_;
+  // True iff the plugin was blocked because the page was being prerendered.
+  // Plugin will automatically be loaded when the page is displayed.
+  bool is_blocked_for_prerendering_;
 };
 
 #endif  // CHROME_RENDERER_BLOCKED_PLUGIN_H_