Start of hardware overlay support in CC with Ubercompositor.

cc/output/overlay_renderer.h

Index: cc/output/overlay_renderer.h
diff --git a/cc/output/overlay_renderer.h b/cc/output/overlay_renderer.h
new file mode 100644
index 0000000000000000000000000000000000000000..7bcc175451d0db7f010b59f130d6758043bf71b0
--- /dev/null
+++ b/cc/output/overlay_renderer.h
@@ -0,0 +1,37 @@
+// 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_RENDERER_H_
+#define CC_OUTPUT_OVERLAY_RENDERER_H_
+
+#include "base/basictypes.h"
+#include "base/memory/scoped_ptr.h"
+#include "cc/base/cc_export.h"
+#include "cc/quads/render_pass.h"
+
+namespace cc {
+class OutputSurface;
+class ResourceProvider;
+
+class CC_EXPORT OverlayRenderer {

[piman, 2014/03/14 03:42:34]

Naming nit: OverlayRenderer sounds like it derives from cc::Renderer, i.e. be an
alternative for GLRenderer or something. Any alternative you could think of?

[enne (OOO), 2014/03/14 18:13:41]

OverlayProcessor? OverlayPassProcessor?

[alexst (slow to review), 2014/03/14 19:54:22]

Maybe OverlayStrategyProcessor?

+ public:
+  class Strategy {
+   public:
+    virtual ~Strategy() {}
+    virtual bool Attempt(RenderPassList* render_passes_in_draw_order) = 0;

[piman, 2014/03/14 03:42:34]

Could you document a bit the contract? It sounds like it returns true if it
promoted at least one (or all?) overlay, and iff it returns true it would have
mutated the RenderPassList?

+  };
+  virtual ~OverlayRenderer();
+  OverlayRenderer(OutputSurface* surface, ResourceProvider* resource_provider);
+
+  void ProcessForOverlays(RenderPassList* render_passes_in_draw_order);
+
+ private:
+  typedef ScopedPtrVector<Strategy> StrategyList;
+  StrategyList strategies_;
+  DISALLOW_COPY_AND_ASSIGN(OverlayRenderer);
+};
+
+}  // namespace cc
+
+#endif  // CC_OUTPUT_OVERLAY_RENDERER_H_