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

cc/trees/layer_tree_host_common_unittest.cc

Index: cc/trees/layer_tree_host_common_unittest.cc
diff --git a/cc/trees/layer_tree_host_common_unittest.cc b/cc/trees/layer_tree_host_common_unittest.cc
index 5101cebe8e34bf37b49cac36767b9ef803922121..f89c3e3c23e9ce9a6629702f4a7fb833492e53d8 100644
--- a/cc/trees/layer_tree_host_common_unittest.cc
+++ b/cc/trees/layer_tree_host_common_unittest.cc
@@ -3709,6 +3709,7 @@ TEST_F(LayerTreeHostCommonTest,
   root->test_properties()->AddChild(std::move(child));
   root->test_properties()->AddChild(std::move(occluding_child));
   host_impl.active_tree()->SetRootLayer(std::move(root));
+  host_impl.active_tree()->BuildLayerListForTesting();
   host_impl.SetVisible(true);
   host_impl.InitializeRenderer(output_surface.get());
   host_impl.active_tree()->BuildLayerListAndPropertyTreesForTesting();
@@ -5265,6 +5266,7 @@ class LCDTextTest : public LayerTreeHostCommonTestBase,
     child_->test_properties()->AddChild(std::move(grand_child_ptr));
     root_->test_properties()->AddChild(std::move(child_ptr));
     host_impl_.active_tree()->SetRootLayer(std::move(root_ptr));
+    host_impl_.active_tree()->BuildLayerListForTesting();
 
     root_->SetContentsOpaque(true);
     child_->SetContentsOpaque(true);
@@ -5479,6 +5481,7 @@ TEST_F(LayerTreeHostCommonTest, SubtreeHidden_SingleLayerImpl) {
   root->test_properties()->AddChild(std::move(child));
   root->SetHasRenderSurface(true);
   host_impl.pending_tree()->SetRootLayer(std::move(root));
+  host_impl.pending_tree()->BuildLayerListForTesting();
 
   LayerImplList render_surface_layer_list;
   LayerTreeHostCommon::CalcDrawPropsImplInputsForTesting inputs(
@@ -5529,6 +5532,7 @@ TEST_F(LayerTreeHostCommonTest, SubtreeHidden_TwoLayersImpl) {
   child->test_properties()->AddChild(std::move(grand_child));
   root->test_properties()->AddChild(std::move(child));
   host_impl.pending_tree()->SetRootLayer(std::move(root));
+  host_impl.pending_tree()->BuildLayerListForTesting();
 
   LayerImplList render_surface_layer_list;
   LayerTreeHostCommon::CalcDrawPropsImplInputsForTesting inputs(
@@ -5629,6 +5633,7 @@ TEST_F(LayerTreeHostCommonTest, SubtreeHiddenWithCopyRequest) {
   root->test_properties()->AddChild(std::move(copy_grand_parent));
   root->test_properties()->AddChild(std::move(copy_grand_parent_sibling_after));
   host_impl.pending_tree()->SetRootLayer(std::move(root));
+  host_impl.pending_tree()->BuildLayerListForTesting();
 
   // Hide the copy_grand_parent and its subtree. But make a copy request in that
   // hidden subtree on copy_layer. Also hide the copy grand child and its