cc: CapturePostTask in SingleThreadProxy::Stop

Impl side posts callbacks for releasing resources on
SingleThreadProxy::Stop, and there is no reason to have these be real
post tasks.

BUG=344087

Review URL: https://codereview.chromium.org/284233005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@271063 0039d316-1c4b-4281-b951-d872f2087c98

cc/trees/single_thread_proxy.cc

@@ -219,6 +219,7 @@ void SingleThreadProxy::Stop() {
     DebugScopedSetMainThreadBlocked main_thread_blocked(this);
     DebugScopedSetImplThread impl(this);
 
+    BlockingTaskRunner::CapturePostTasks blocked;
     layer_tree_host_->DeleteContentsTexturesOnImplThread(
         layer_tree_host_impl_->resource_provider());
     layer_tree_host_impl_.reset();