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

cc/thread_proxy.cc

Index: cc/thread_proxy.cc
diff --git a/cc/thread_proxy.cc b/cc/thread_proxy.cc
index ab708613204ecbc672900ca71bdb6abdef33994b..4cdbca173461906d598bb3ba295e51b85dfe589f 100644
--- a/cc/thread_proxy.cc
+++ b/cc/thread_proxy.cc
@@ -12,6 +12,7 @@
 #include "cc/input_handler.h"
 #include "cc/layer_tree_host.h"
 #include "cc/output_surface.h"
+#include "cc/picture_pile_impl.h"
 #include "cc/scheduler.h"
 #include "cc/thread.h"
 #include "third_party/WebKit/Source/Platform/chromium/public/WebSharedGraphicsContext3D.h"
@@ -1019,4 +1020,27 @@ void ThreadProxy::commitPendingOnImplThreadForTesting(CommitPendingRequest* requ
     request->completion.signal();
 }
 
+scoped_refptr<PicturePileImpl> ThreadProxy::capturePicturePile()
+{
+    DCHECK(isMainThread());
+    CompletionEvent completion;
+    scoped_refptr<PicturePileImpl> picture_pile;
+    {
+        DebugScopedSetMainThreadBlocked mainThreadBlocked(this);
+        Proxy::implThread()->postTask(base::Bind(&ThreadProxy::capturePicturePileOnImplThread,
+                                                 m_implThreadWeakPtr,
+                                                 &completion,
+                                                 &picture_pile));
+        completion.wait();
+    }
+    return picture_pile;
+}
+
+void ThreadProxy::capturePicturePileOnImplThread(CompletionEvent* completion, scoped_refptr<PicturePileImpl>* picture_pile)
+{
+    DCHECK(isImplThread());
+    *picture_pile = m_layerTreeHostImpl->capturePicturePile();
+    completion->signal();
+}
+
 }  // namespace cc