Fixes issues when switching between software and compositing.

content/renderer/browser_plugin/browser_plugin_manager_impl.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_manager_impl.h"
 
 #include "content/common/browser_plugin_messages.h"
 #include "content/renderer/browser_plugin/browser_plugin.h"
 #include "content/renderer/render_thread_impl.h"
 #include "ui/gfx/point.h"
@@ skipping 31 matching lines @@
     PickleIterator iter(message);
     bool success = iter.ReadInt(&instance_id);
     DCHECK(success);
     BrowserPlugin* plugin = GetBrowserPlugin(instance_id);
     if (plugin && plugin->OnMessageReceived(message))
       return true;
   }
 
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP(BrowserPluginManagerImpl, message)
+    IPC_MESSAGE_HANDLER(BrowserPluginMsg_BuffersSwapped,
+                        OnUnhandledSwap);
     IPC_MESSAGE_HANDLER(BrowserPluginMsg_PluginAtPositionRequest,
                         OnPluginAtPositionRequest);
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
   return handled;
 }
 
 void BrowserPluginManagerImpl::OnPluginAtPositionRequest(
     const IPC::Message& message,
     int request_id,
@@ skipping 15 matching lines @@
     it.Advance();
   }
 
   Send(new BrowserPluginHostMsg_PluginAtPositionResponse(
        source_routing_id,
        instance_id,
        request_id,
        local_position));
 }
 
+void BrowserPluginManagerImpl::OnUnhandledSwap(const IPC::Message& message,
+                                               int instance_id,
+                                               const gfx::Size& size,
+                                               std::string mailbox_name,
+                                               int gpu_route_id,
+                                               int gpu_host_id) {
+  // After the BrowserPlugin object sends a destroy message to the
+  // guest, it goes away and is unable to handle messages that
+  // might still be coming from the guest.
+  // In this case, we might receive a BuffersSwapped message that
+  // we need to ACK.
+  // Issue is tracked in crbug.com/170745.
+  Send(new BrowserPluginHostMsg_BuffersSwappedACK(
+      message.routing_id(),
+      gpu_route_id,
+      gpu_host_id,
+      mailbox_name,
+      0));
+}
+
 // static
 bool BrowserPluginManagerImpl::ShouldForwardToBrowserPlugin(
     const IPC::Message& message) {
   switch (message.type()) {
     case BrowserPluginMsg_AdvanceFocus::ID:
     case BrowserPluginMsg_GuestContentWindowReady::ID:
     case BrowserPluginMsg_GuestGone::ID:
     case BrowserPluginMsg_GuestResponsive::ID:
     case BrowserPluginMsg_GuestUnresponsive::ID:
     case BrowserPluginMsg_LoadAbort::ID:
     case BrowserPluginMsg_LoadCommit::ID:
     case BrowserPluginMsg_LoadRedirect::ID:
     case BrowserPluginMsg_LoadStart::ID:
     case BrowserPluginMsg_LoadStop::ID:
     case BrowserPluginMsg_SetCursor::ID:
     case BrowserPluginMsg_ShouldAcceptTouchEvents::ID:
     case BrowserPluginMsg_UpdatedName::ID:
     case BrowserPluginMsg_UpdateRect::ID:
     case BrowserPluginMsg_BuffersSwapped::ID:
       return true;
     default:
       break;
   }
   return false;
 }
 
 }  // namespace content