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

cc/single_thread_proxy.cc

Index: cc/single_thread_proxy.cc
diff --git a/cc/single_thread_proxy.cc b/cc/single_thread_proxy.cc
index 91ac9520dd780d09804535fc3962a793fd1a3fce..5a250a1f37c2ba2b4c558593b93e731dcc6743f8 100644
--- a/cc/single_thread_proxy.cc
+++ b/cc/single_thread_proxy.cc
@@ -404,4 +404,11 @@ bool SingleThreadProxy::commitPendingForTesting()
     return false;
 }
 
+skia::RefPtr<SkPicture> SingleThreadProxy::capturePicture()
+{
+    // Requires impl-side painting, which is only supported in threaded compositing.
+    NOTREACHED();
+    return skia::RefPtr<SkPicture>();
+}
+
 }  // namespace cc