Shouldn't access LayerTreeTest::layer_tree_host on impl thread

cc/trees/single_thread_proxy.cc

Index: cc/trees/single_thread_proxy.cc
diff --git a/cc/trees/single_thread_proxy.cc b/cc/trees/single_thread_proxy.cc
index 7534b4d0192f7d2d51bfdbc97ce5323051a5ad81..38d83e2f34a3064424ee3d931dfab9a618b42d1b 100644
--- a/cc/trees/single_thread_proxy.cc
+++ b/cc/trees/single_thread_proxy.cc
@@ -106,7 +106,7 @@ void SingleThreadProxy::SetSurfaceReady() {
 }
 
 void SingleThreadProxy::SetVisible(bool visible) {
-  DebugScopedSetImplThread impl(this);
+  DebugScopedSetImplThreadAndMainThreadBlocked impl(this);
   layer_tree_host_impl_->SetVisible(visible);
 }
 
@@ -183,9 +183,7 @@ void SingleThreadProxy::DoCommit(scoped_ptr<ResourceUpdateQueue> queue) {
   DCHECK(Proxy::IsMainThread());
   // Commit immediately.
   {
-    DebugScopedSetMainThreadBlocked mainThreadBlocked(this);
-    DebugScopedSetImplThread impl(this);
-
+    DebugScopedSetImplThreadAndMainThreadBlocked impl_and_main_blocked(this);

[danakj, 2013/04/25 20:56:57]

nit: s/and/with/ (theyre not both blocked)

     RenderingStatsInstrumentation* stats_instrumentation =
         layer_tree_host_->rendering_stats_instrumentation();
     base::TimeTicks start_time = stats_instrumentation->StartRecording();