gpu: don't try to discard/recreate backbuffer while draws are deferred.

content/common/gpu/texture_image_transport_surface.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/common/gpu/texture_image_transport_surface.h"
 
 #include <string>
 #include <vector>
 
 #include "base/command_line.h"
@@ skipping 157 matching lines @@
   }
 
   return true;
 }
 
 unsigned int TextureImageTransportSurface::GetBackingFrameBufferObject() {
   return fbo_id_;
 }
 
 void TextureImageTransportSurface::SetBackbufferAllocation(bool allocation) {
+  DCHECK(!is_swap_buffers_pending_);
   if (backbuffer_suggested_allocation_ == allocation)
      return;
   backbuffer_suggested_allocation_ = allocation;
 
   if (!helper_->MakeCurrent())
     return;
 
   if (backbuffer_suggested_allocation_) {
     DCHECK(!textures_[back()].info->service_id() ||
            !textures_[back()].sent_to_client);
@@ skipping 373 matching lines @@
     if (!texture.sent_to_client)
       continue;
     GpuHostMsg_AcceleratedSurfaceRelease_Params params;
     params.identifier = texture.client_id;
     helper_->SendAcceleratedSurfaceRelease(params);
   }
   parent_stub_ = NULL;
 }
 
 }  // namespace content