cc: Async readback.

Provide a path to get a readback of a layer's subtree via an
asynchronous mechanism.

This path is used for all the cc pixel tests, to show that it
works. Also by some unit tests:

LayerTreeHostTestAsyncReadback.GLRenderer_RunSingleThread
LayerTreeHostTestAsyncReadback.GLRenderer_RunMultiThread
LayerTreeHostTestAsyncReadback.SoftwareRenderer_RunSingleThread
LayerTreeHostTestAsyncReadback.SoftwareRenderer_RunMultiThread
LayerTreeHostTestAsyncReadbackLayerDestroyed.RunSingleThread
LayerTreeHostTestAsyncReadbackLayerDestroyed.RunMultiThread

BUG=179896

Review URL: https://chromiumcodereview.appspot.com/14060015

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@196713 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 10 insertions, 0 deletions

diff --git a/cc/quads/render_pass.h b/cc/quads/render_pass.h
index bfd0d83..1fb011a 100644
--- a/cc/quads/render_pass.h
+++ b/cc/quads/render_pass.h
@@ -9,6 +9,8 @@
 #include <vector>
 
 #include "base/basictypes.h"
+#include "base/callback.h"
+#include "base/hash_tables.h"
 #include "cc/base/cc_export.h"
 #include "cc/base/hash_pair.h"
 #include "cc/base/scoped_ptr_hash_map.h"
@@ -97,6 +99,14 @@ class CC_EXPORT RenderPass {
   // complete, since they are occluded.
   bool has_occlusion_from_outside_target_surface;
 
+  // If non-empty, the renderer should produce a copy of the render pass'
+  // contents as a bitmap, and give a copy of the bitmap to each callback in
+  // this list. This property should not be serialized between compositors, as
+  // it only makes sense in the root compositor.
+  typedef base::Callback<void(scoped_ptr<SkBitmap>)>
+      RequestCopyAsBitmapCallback;
+  std::vector<RequestCopyAsBitmapCallback> copy_callbacks;
+
   QuadList quad_list;
   SharedQuadStateList shared_quad_state_list;