Do not give GPU memory to backgrounded compositors.

content/renderer/gpu/compositor_output_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/renderer/gpu/compositor_output_surface.h"
 
 #include "base/command_line.h"
 #include "base/message_loop/message_loop_proxy.h"
 #include "cc/output/compositor_frame.h"
 #include "cc/output/compositor_frame_ack.h"
@@ skipping 86 matching lines @@
   output_surface_filter_->AddRoute(
       routing_id_,
       base::Bind(&CompositorOutputSurfaceProxy::OnMessageReceived,
                  output_surface_proxy_));
 
   if (!context_provider()) {
     // Without a GPU context, the memory policy otherwise wouldn't be set.
     client->SetMemoryPolicy(cc::ManagedMemoryPolicy(
         64 * 1024 * 1024,
         gpu::MemoryAllocation::CUTOFF_ALLOW_NICE_TO_HAVE,
-        0,
-        gpu::MemoryAllocation::CUTOFF_ALLOW_NOTHING,
         cc::ManagedMemoryPolicy::kDefaultNumResourcesLimit));
   }
 
   return true;
 }
 
 void CompositorOutputSurface::SwapBuffers(cc::CompositorFrame* frame) {
   if (use_swap_compositor_frame_message_) {
     Send(new ViewHostMsg_SwapCompositorFrame(routing_id_,
                                              output_surface_id_,
@@ skipping 109 matching lines @@
   // If this is the last surface to stop preferring smoothness,
   // Reset the main thread's priority to the default.
   if (prefers_smoothness_ == true &&
       --g_prefer_smoothness_count == 0) {
     SetThreadPriorityToDefault(main_thread_handle_);
   }
   prefers_smoothness_ = prefers_smoothness;
 }
 
 }  // namespace content