cc: Add image decode queue functionality to image manager.

ui/compositor/compositor.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 "ui/compositor/compositor.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <deque>
@@ skipping 189 matching lines @@
   base::TimeTicks before_create = base::TimeTicks::Now();
 
   animation_host_ = cc::AnimationHost::CreateMainInstance();
 
   cc::LayerTreeHostInProcess::InitParams params;
   params.client = this;
   params.task_graph_runner = context_factory_->GetTaskGraphRunner();
   params.settings = &settings;
   params.main_task_runner = task_runner_;
   params.mutator_host = animation_host_.get();
+  // TODO(vmpstr): For now, we don't need a task runner in the UI since we don't
+  // use image queue here.
+  params.image_worker_task_runner = nullptr;
   host_ = cc::LayerTreeHostInProcess::CreateSingleThreaded(this, &params);
   UMA_HISTOGRAM_TIMES("GPU.CreateBrowserCompositor",
                       base::TimeTicks::Now() - before_create);
 
   animation_timeline_ =
       cc::AnimationTimeline::Create(cc::AnimationIdProvider::NextTimelineId());
   animation_host_->AddAnimationTimeline(animation_timeline_.get());
 
   host_->GetLayerTree()->SetRootLayer(root_web_layer_);
   host_->SetFrameSinkId(frame_sink_id_);
@@ skipping 344 matching lines @@
   for (auto& observer : observer_list_)
     observer.OnCompositingLockStateChanged(this);
 }
 
 void Compositor::CancelCompositorLock() {
   if (compositor_lock_)
     compositor_lock_->CancelLock();
 }
 
 }  // namespace ui