cc: DCHECK that the OutputSurface was released in ~LayerTreeHostImpl().

cc/test/fake_layer_tree_host_impl.cc

Index: cc/test/fake_layer_tree_host_impl.cc
diff --git a/cc/test/fake_layer_tree_host_impl.cc b/cc/test/fake_layer_tree_host_impl.cc
index a0b9f48647e9f531105a5e362565c9c91a06beeb..d58fee19b93af020b52c904dcfc8a1d6eadd5be7 100644
--- a/cc/test/fake_layer_tree_host_impl.cc
+++ b/cc/test/fake_layer_tree_host_impl.cc
@@ -62,7 +62,9 @@ FakeLayerTreeHostImpl::FakeLayerTreeHostImpl(
       CreateBeginFrameArgsForTesting(BEGINFRAME_FROM_HERE, time_ticks));
 }
 
-FakeLayerTreeHostImpl::~FakeLayerTreeHostImpl() {}
+FakeLayerTreeHostImpl::~FakeLayerTreeHostImpl() {
+  ReleaseOutputSurface();
+}
 
 void FakeLayerTreeHostImpl::CreatePendingTree() {
   LayerTreeHostImpl::CreatePendingTree();