Add logic to GLRenderer to support RenderPassDrawQuad copying.

cc/output/ca_layer_overlay.h

Index: cc/output/ca_layer_overlay.h
diff --git a/cc/output/ca_layer_overlay.h b/cc/output/ca_layer_overlay.h
index e26145c93f48f514793bdc18f8d17f0a78851f80..4f1c1b1fd145c5386026011d77528835469f8051 100644
--- a/cc/output/ca_layer_overlay.h
+++ b/cc/output/ca_layer_overlay.h
@@ -6,6 +6,7 @@
 #define CC_OUTPUT_CA_LAYER_OVERLAY_H_
 
 #include "base/memory/ref_counted.h"
+#include "cc/base/resource_id.h"
 #include "cc/quads/render_pass.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "third_party/skia/include/core/SkMatrix44.h"
@@ -39,6 +40,20 @@ class CC_EXPORT CALayerOverlaySharedState
   ~CALayerOverlaySharedState() {}
 };
 

[ccameron, 2016/07/20 05:32:19]

I'd advocate just stuffing the CopyRenderPassDrawQuadToIOSurface method into
cc::DirectRenderer directly.

[erikchen, 2016/07/20 21:48:01]

Done.

+class RenderPassDrawQuadCopier {
+ public:
+  // On success, the resource will be marked as in-use and will not be reused
+  // until the gpu process has marked the resource as no longer in use. The
+  // caller is required to send the IOSurface to the gpu process.
+  virtual bool CopyRenderPassDrawQuadToIOSurface(const RenderPassDrawQuad* quad,
+                                                 ResourceId* resource_id) = 0;
+  // Immediately releases the IOSurface-backed resources for reuse or deletion.
+  virtual void ReleaseIOSurfaces(const std::vector<ResourceId>& resources) = 0;

[ccameron, 2016/07/20 05:32:19]

ReleaseIOSurfaces appears only to be called from within GLRenderer (here and in
https://codereview.chromium.org/2164613003/) -- let's keep it out of the
interface.

[erikchen, 2016/07/20 21:48:01]

Done.

+  // Informs the RenderPassDrawQuadCopier of the number of copied IOSurfaces for
+  // the current frame, which will affect the IOSurface cache size.
+  virtual void UpdateCopyCountForFrame(size_t count) = 0;

[ccameron, 2016/07/20 05:32:19]

This appears only to be called in testing code. Can it go?

[erikchen, 2016/07/20 21:48:01]

Done.

+};
+
 // Holds all information necessary to construct a CALayer from a DrawQuad.
 class CC_EXPORT CALayerOverlay {
  public: