Start of hardware overlay support in CC with Ubercompositor.

cc/output/overlay_strategy_single_on_top.h

Index: cc/output/overlay_strategy_single_on_top.h
diff --git a/cc/output/overlay_strategy_single_on_top.h b/cc/output/overlay_strategy_single_on_top.h
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+// Copyright 2014 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.
+
+#ifndef CC_OUTPUT_OVERLAY_STRATEGY_SINGLE_ON_TOP_H_
+#define CC_OUTPUT_OVERLAY_STRATEGY_SINGLE_ON_TOP_H_
+
+#include "base/basictypes.h"
+#include "base/memory/scoped_ptr.h"
+#include "cc/base/cc_export.h"
+#include "cc/output/overlay_processor.h"
+#include "cc/quads/render_pass.h"
+
+namespace cc {
+class OverlayCandidateValidator;
+
+class CC_EXPORT OverlayStrategySingleOnTop : public OverlayProcessor::Strategy {
+ public:
+  OverlayStrategySingleOnTop(OverlayCandidateValidator* capability_checker,
+                             ResourceProvider* resource_provider);
+  virtual bool Attempt(RenderPassList* render_passes_in_draw_order) OVERRIDE;
+
+ private:
+  OverlayCandidateValidator* capability_checker_;
+  ResourceProvider* resource_provider_;
+  DISALLOW_COPY_AND_ASSIGN(OverlayStrategySingleOnTop);
+};
+
+}  // namespace cc
+
+#endif  // CC_OUTPUT_OVERLAY_STRATEGY_SINGLE_ON_TOP_H_