Enable the Sky compositor

sky/compositor/layer_host.cc

Index: sky/compositor/layer_host.cc
diff --git a/sky/compositor/layer_host.cc b/sky/compositor/layer_host.cc
index a00dbd98c194248345da9072f89c75d0b14b3729..a1991770c3b4a827fc12f5835b09c1ecaf06d38c 100644
--- a/sky/compositor/layer_host.cc
+++ b/sky/compositor/layer_host.cc
@@ -49,7 +49,13 @@ void LayerHost::ReturnResources(
 void LayerHost::BeginFrame(base::TimeTicks frame_time,
                            base::TimeTicks deadline) {
   client_->BeginFrame(frame_time);
-  root_layer_->Display();
+
+  {
+    mojo::GaneshContext::Scope scope(&ganesh_context_);
+    ganesh_context_.gr()->resetContext();

[esprehn, 2014/11/21 17:53:19]

Why not do this inside the Display() call like before?

[abarth-chromium, 2014/11/21 17:56:52]

It doesn't really matter today because we only have one Layer.  I've tried to
set things up so that we can have more than one layer (e.g., between each child
mojo::View).  Conceptually, we should only enter Ganesh mode once and then draw
all the layers, which is why I moved this here.

+    root_layer_->Display();
+  }
+
   Upload(root_layer_.get());
 }