cc: Fix missing render surfaces with output requests

cc/trees/thread_proxy.cc

Index: cc/trees/thread_proxy.cc
diff --git a/cc/trees/thread_proxy.cc b/cc/trees/thread_proxy.cc
index b72f03cf61cd791c3b75917cdb333d3a880f79e8..286ae735dcd980f312de222410a8255721a71c66 100644
--- a/cc/trees/thread_proxy.cc
+++ b/cc/trees/thread_proxy.cc
@@ -154,9 +154,9 @@ bool ThreadProxy::IsStarted() const {
 }
 
 bool ThreadProxy::CommitToActiveTree() const {
-  // With ThreadProxy we use a pending tree and activate it once it's ready to
-  // draw.
-  return false;
+  // With ThreadProxy and impl-side painting, we use a pending tree and activate
+  // it once it's ready to draw.
+  return !impl().layer_tree_host_impl->settings().impl_side_painting;
 }
 
 void ThreadProxy::SetLayerTreeHostClientReady() {