SubtreeShouldBeSkipped uses information from property trees

cc/trees/occlusion_tracker_unittest.cc

Index: cc/trees/occlusion_tracker_unittest.cc
diff --git a/cc/trees/occlusion_tracker_unittest.cc b/cc/trees/occlusion_tracker_unittest.cc
index 5aa72c39f300f704acc2d4b13896f92699205057..e5d0927de0a63be6adc44fa0b6f564e97e9b24d2 100644
--- a/cc/trees/occlusion_tracker_unittest.cc
+++ b/cc/trees/occlusion_tracker_unittest.cc
@@ -105,10 +105,11 @@ class OcclusionTrackerTest : public testing::Test {
     TestContentLayerImpl* layer_ptr = layer.get();
     SetProperties(layer_ptr, transform, position, bounds);
 
-    host_->host_impl()->active_tree()->SetRootLayer(std::move(layer));
+    root_ = layer.get();

[ajuma, 2016/03/24 15:12:00]

Are the changes in this file needed? In particular, rather than hanging on to a
raw pointer to the root, can we continue to get the root from the LayerTreeImpl
when we need it, as before?

[sunxd, 2016/03/29 14:26:34]

Done.

 
     layer_ptr->SetForceRenderSurface(true);
     SetRootLayerOnMainThread(layer_ptr);
+    tree->SetRootLayer(std::move(layer));
 
     return layer_ptr;
   }
@@ -218,7 +219,7 @@ class OcclusionTrackerTest : public testing::Test {
   }
 
   void CalcDrawEtc(TestContentLayerImpl* root) {
-    DCHECK(root == root->layer_tree_impl()->root_layer());
+    DCHECK(root == root_);
 
     // These occlusion tests attach and detach layers in multiple
     // iterations, so rebuild property trees every time.
@@ -310,6 +311,7 @@ class OcclusionTrackerTest : public testing::Test {
   TestTaskGraphRunner task_graph_runner_;
   scoped_ptr<FakeLayerTreeHost> host_;
   // These hold ownership of the layers for the duration of the test.
+  LayerImpl* root_;
   LayerImplList render_surface_layer_list_impl_;
   LayerIterator layer_iterator_begin_;
   LayerIterator layer_iterator_;