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

chrome/common/render_messages_params.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_COMMON_RENDER_MESSAGES_PARAMS_H_
 #define CHROME_COMMON_RENDER_MESSAGES_PARAMS_H_
 #pragma once
 
 #include <string>
 #include <vector>
@@ skipping 44 matching lines @@
     // Reload the page, ignoring any cache entries.
     RELOAD_IGNORING_CACHE,
 
     // The navigation is the result of session restore and should honor the
     // page's cache policy while restoring form state. This is set to true if
     // restoring a tab/session from the previous session and the previous
     // session did not crash. If this is not set and the page was restored then
     // the page's cache policy is ignored and we load from the cache.
     RESTORE,
 
+    // Speculatively prerendering the page.
+    PRERENDER,
+
     // Navigation type not categorized by the other types.
     NORMAL
   };
 
   ViewMsg_Navigate_Params();
   ~ViewMsg_Navigate_Params();
 
   // The page_id for this navigation, or -1 if it is a new navigation.  Back,
   // Forward, and Reload navigations should have a valid page_id.  If the load
   // succeeds, then this page_id will be reflected in the resultant
@@ skipping 1060 matching lines @@
 struct ParamTraits<ViewHostMsg_AccessibilityNotification_Params> {
   typedef ViewHostMsg_AccessibilityNotification_Params param_type;
   static void Write(Message* m, const param_type& p);
   static bool Read(const Message* m, void** iter, param_type* p);
   static void Log(const param_type& p, std::string* l);
 };
 
 }  // namespace IPC
 
 #endif  // CHROME_COMMON_RENDER_MESSAGES_PARAMS_H_