Support single-threaded impl-side painting

cc/test/layer_tree_test.cc

Index: cc/test/layer_tree_test.cc
diff --git a/cc/test/layer_tree_test.cc b/cc/test/layer_tree_test.cc
index c19c63f09f1ca22dccc24822a8716e7cdbc8a728..18c32c4310609d0e959c86ecf8b69b1eb3ff1ad7 100644
--- a/cc/test/layer_tree_test.cc
+++ b/cc/test/layer_tree_test.cc
@@ -513,6 +513,13 @@ void LayerTreeTest::PostSetNextCommitForcesRedrawToMainThread() {
                  main_thread_weak_ptr_));
 }
 
+void LayerTreeTest::PostCompositeImmediatelyToMainThread() {
+  main_task_runner_->PostTask(
+      FROM_HERE,
+      base::Bind(&LayerTreeTest::DispatchCompositeImmediately,
+                 main_thread_weak_ptr_));
+}
+
 void LayerTreeTest::WillBeginTest() {
   layer_tree_host_->SetLayerTreeHostClientReady();
 }
@@ -628,6 +635,12 @@ void LayerTreeTest::DispatchSetNextCommitForcesRedraw() {
     layer_tree_host_->SetNextCommitForcesRedraw();
 }
 
+void LayerTreeTest::DispatchCompositeImmediately() {
+  DCHECK(!proxy() || proxy()->IsMainThread());
+  if (layer_tree_host_)
+    layer_tree_host_->Composite(gfx::FrameTime::Now());
+}
+
 void LayerTreeTest::RunTest(bool threaded,
                             bool delegating_renderer,
                             bool impl_side_painting) {