cc : Clean up cc clip tree

cc/trees/layer_tree_host_unittest.cc

Index: cc/trees/layer_tree_host_unittest.cc
diff --git a/cc/trees/layer_tree_host_unittest.cc b/cc/trees/layer_tree_host_unittest.cc
index 921e22db5a4db4377cce0b3a242af5eff1be2cda..5dafbec5acaccc0c7cfb3825e0e01dc42e35865e 100644
--- a/cc/trees/layer_tree_host_unittest.cc
+++ b/cc/trees/layer_tree_host_unittest.cc
@@ -803,7 +803,7 @@ class LayerTreeHostTestPushNodeOwnerToNodeIdMap : public LayerTreeHostTest {
   void DidCommit() override {
     switch (layer_tree_host()->SourceFrameNumber()) {
       case 1:
-        // child_ should create transform, effect, clip node.
+        // child_ should create transform, effect node.
         child_->SetForceRenderSurfaceForTesting(true);
         break;
       case 2:
@@ -811,7 +811,12 @@ class LayerTreeHostTestPushNodeOwnerToNodeIdMap : public LayerTreeHostTest {
         child_->SetScrollClipLayerId(root_->id());
         break;
       case 3:
+        // child_ should create a clip node.
+        child_->SetMasksToBounds(true);
+        break;
+      case 4:
         // child_ should not create any property tree node.
+        child_->SetMasksToBounds(false);
         child_->SetForceRenderSurfaceForTesting(false);
         child_->SetScrollClipLayerId(Layer::INVALID_ID);
     }
@@ -837,8 +842,8 @@ class LayerTreeHostTestPushNodeOwnerToNodeIdMap : public LayerTreeHostTest {
         property_trees->layer_id_to_scroll_node_index.find(child_->id());
     switch (impl->sync_tree()->source_frame_number()) {
       case 0:
-        // root_ should create every property tree node and child_ should not
-        // create any.
+        // root_ should create transform, scroll and effect tree nodes but not
+        // a clip node.
         EXPECT_NE(root_transform_id_to_index,
                   property_trees->layer_id_to_transform_node_index.end());
         EXPECT_EQ(root_transform_id_to_index->second,
@@ -846,12 +851,11 @@ class LayerTreeHostTestPushNodeOwnerToNodeIdMap : public LayerTreeHostTest {
         EXPECT_NE(root_effect_id_to_index,
                   property_trees->layer_id_to_effect_node_index.end());
         EXPECT_EQ(root_effect_id_to_index->second, root_->effect_tree_index());
-        EXPECT_NE(root_clip_id_to_index,
-                  property_trees->layer_id_to_clip_node_index.end());
-        EXPECT_EQ(root_clip_id_to_index->second, root_->clip_tree_index());
         EXPECT_NE(root_scroll_id_to_index,
                   property_trees->layer_id_to_scroll_node_index.end());
         EXPECT_EQ(root_scroll_id_to_index->second, root_->scroll_tree_index());
+        EXPECT_EQ(root_clip_id_to_index,
+                  property_trees->layer_id_to_clip_node_index.end());
         EXPECT_EQ(child_transform_id_to_index,
                   property_trees->layer_id_to_transform_node_index.end());
         EXPECT_EQ(child_effect_id_to_index,
@@ -862,7 +866,7 @@ class LayerTreeHostTestPushNodeOwnerToNodeIdMap : public LayerTreeHostTest {
                   property_trees->layer_id_to_scroll_node_index.end());
         break;
       case 1:
-        // child_ should create a transfrom, clip, effect nodes but not a scroll
+        // child_ should create a transfrom, effect nodes but not a scroll, clip
         // node.
         EXPECT_NE(
             property_trees->layer_id_to_transform_node_index.find(child_->id()),
@@ -874,10 +878,9 @@ class LayerTreeHostTestPushNodeOwnerToNodeIdMap : public LayerTreeHostTest {
             property_trees->layer_id_to_effect_node_index.end());
         EXPECT_EQ(child_effect_id_to_index->second,
                   child_->effect_tree_index());
-        EXPECT_NE(
+        EXPECT_EQ(
             property_trees->layer_id_to_clip_node_index.find(child_->id()),
             property_trees->layer_id_to_clip_node_index.end());
-        EXPECT_EQ(child_clip_id_to_index->second, child_->clip_tree_index());
         EXPECT_EQ(
             property_trees->layer_id_to_scroll_node_index.find(child_->id()),
             property_trees->layer_id_to_scroll_node_index.end());
@@ -891,6 +894,13 @@ class LayerTreeHostTestPushNodeOwnerToNodeIdMap : public LayerTreeHostTest {
                   child_->scroll_tree_index());
         break;
       case 3:
+        // child_ should create a clip node.
+        EXPECT_NE(
+            property_trees->layer_id_to_clip_node_index.find(child_->id()),
+            property_trees->layer_id_to_clip_node_index.end());
+        EXPECT_EQ(child_clip_id_to_index->second, child_->clip_tree_index());
+        break;
+      case 4:
         // child_ should not create any property tree nodes.
         EXPECT_EQ(
             property_trees->layer_id_to_transform_node_index.find(child_->id()),