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

content/common/gpu/gpu_command_buffer_stub.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.
 
 #if defined(ENABLE_GPU)
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
@@ skipping 696 matching lines @@
 void GpuCommandBufferStub::OnSetSurfaceVisible(bool visible) {
   TRACE_EVENT0("gpu", "GpuCommandBufferStub::OnSetSurfaceVisible");
   GetMemoryManager()->
       SetClientVisible(this, visible);
 }
 
 void GpuCommandBufferStub::OnDiscardBackbuffer() {
   TRACE_EVENT0("gpu", "GpuCommandBufferStub::OnDiscardBackbuffer");
   if (!surface_)
     return;
-  surface_->SetBackbufferAllocation(false);
+  if (surface_->DeferDraws()) {
+    DCHECK(!IsScheduled());
+    channel_->RequeueMessage();
+  } else {
+    surface_->SetBackbufferAllocation(false);
+  }
 }
 
 void GpuCommandBufferStub::OnEnsureBackbuffer() {
   TRACE_EVENT0("gpu", "GpuCommandBufferStub::OnEnsureBackbuffer");
   if (!surface_)
     return;
-  surface_->SetBackbufferAllocation(true);
+  if (surface_->DeferDraws()) {
+    DCHECK(!IsScheduled());
+    channel_->RequeueMessage();
+  } else {
+    surface_->SetBackbufferAllocation(true);
+  }
 }
 
 void GpuCommandBufferStub::AddSyncPoint(uint32 sync_point) {
   sync_points_.push_back(sync_point);
 }
 
 void GpuCommandBufferStub::OnRetireSyncPoint(uint32 sync_point) {
   DCHECK(!sync_points_.empty() && sync_points_.front() == sync_point);
   sync_points_.pop_front();
   GpuChannelManager* manager = channel_->gpu_channel_manager();
@@ skipping 114 matching lines @@
   // made current before calling methods on the surface.
   if (!surface_ || !MakeCurrent())
     return;
   surface_->SetFrontbufferAllocation(
       allocation.browser_allocation.suggest_have_frontbuffer);
 }
 
 }  // namespace content
 
 #endif  // defined(ENABLE_GPU)