Fixes issues when switching between software and compositing.

content/renderer/browser_plugin/browser_plugin.cc

 // Copyright (c) 2012 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.
 
 #include "content/renderer/browser_plugin/browser_plugin.h"
 
 #include "base/json/json_string_value_serializer.h"
 #include "base/message_loop.h"
 #include "base/string_number_conversions.h"
 #include "base/string_util.h"
@@ skipping 799 matching lines @@
   container_ = container;
   container_->setWantsWheelEvents(true);
   return true;
 }
 
 void BrowserPlugin::EnableCompositing(bool enable) {
   if (compositing_enabled_ == enable)
     return;
 
   if (enable && !compositing_helper_) {
-    compositing_helper_.reset(new BrowserPluginCompositingHelper(
+    compositing_helper_ = new BrowserPluginCompositingHelper(
         container_,
-        render_view_routing_id_));
+        render_view_routing_id_);
   }
 
   compositing_helper_->EnableCompositing(enable);
   compositing_enabled_ = enable;
 }
 
 void BrowserPlugin::destroy() {
   // The BrowserPlugin's WebPluginContainer is deleted immediately after this
   // call returns, so let's not keep a reference to it around.
   container_ = NULL;
-  compositing_helper_.reset();
+  if (compositing_helper_)
+    compositing_helper_->OnContainerDestroy();
   MessageLoop::current()->DeleteSoon(FROM_HERE, this);
 }
 
 NPObject* BrowserPlugin::scriptableObject() {
   NPObject* browser_plugin_np_object(bindings_->np_object());
   // The object is expected to be retained before it is returned.
   WebKit::WebBindings::retainObject(browser_plugin_np_object);
   return browser_plugin_np_object;
 }
 
@@ skipping 255 matching lines @@
                                                  void* notify_data) {
 }
 
 void BrowserPlugin::didFailLoadingFrameRequest(
     const WebKit::WebURL& url,
     void* notify_data,
     const WebKit::WebURLError& error) {
 }
 
 }  // namespace content