Implement a method to access the non-composited content root layer picture pile.

cc/layer_tree_host.h

Index: cc/layer_tree_host.h
diff --git a/cc/layer_tree_host.h b/cc/layer_tree_host.h
index 95766e342c4fb8b72c3ae916122a6da4e712e756..b8483260e0dd462a6b05b92a3cec402bcbd7a2ea 100644
--- a/cc/layer_tree_host.h
+++ b/cc/layer_tree_host.h
@@ -20,6 +20,7 @@
 #include "cc/layer_tree_settings.h"
 #include "cc/occlusion_tracker.h"
 #include "cc/output_surface.h"
+#include "cc/picture_pile_impl.h"
 #include "cc/prioritized_resource_manager.h"
 #include "cc/proxy.h"
 #include "cc/rate_limiter.h"
@@ -201,6 +202,8 @@ public:
 
     AnimationRegistrar* animationRegistrar() const { return m_animationRegistrar.get(); }
 
+    scoped_refptr<PicturePileImpl> capturePicturePile();
+
 protected:
     LayerTreeHost(LayerTreeHostClient*, const LayerTreeSettings&);
     bool initialize(scoped_ptr<Thread> implThread);