Clarify property tree id-to-index map names.

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 d7bd2169d2ed444240f4228abceec5423c79cd83..7854d628dfcd918cd3fdc49556649c4d792403e8 100644
--- a/cc/trees/layer_tree_host_common_unittest.cc
+++ b/cc/trees/layer_tree_host_common_unittest.cc
@@ -10264,8 +10264,8 @@ TEST_F(LayerTreeHostCommonTest, PropertyTreesRebuildWithOpacityChanges) {
   EXPECT_TRUE(property_trees->needs_rebuild);
 
   ExecuteCalculateDrawPropertiesAndSaveUpdateLayerList(root.get());
-  EXPECT_NE(property_trees->effect_id_to_index_map.find(child->id()),
-            property_trees->effect_id_to_index_map.end());
+  EXPECT_NE(property_trees->layer_id_to_effect_node_index.find(child->id()),
+            property_trees->layer_id_to_effect_node_index.end());
 
   // child already has an effect node. Changing its opacity shouldn't trigger
   // a property trees rebuild.
@@ -10274,8 +10274,8 @@ TEST_F(LayerTreeHostCommonTest, PropertyTreesRebuildWithOpacityChanges) {
   EXPECT_FALSE(property_trees->needs_rebuild);
 
   ExecuteCalculateDrawPropertiesAndSaveUpdateLayerList(root.get());
-  EXPECT_NE(property_trees->effect_id_to_index_map.find(child->id()),
-            property_trees->effect_id_to_index_map.end());
+  EXPECT_NE(property_trees->layer_id_to_effect_node_index.find(child->id()),
+            property_trees->layer_id_to_effect_node_index.end());
 
   // Changing the opacity from non-1 value to 1 should trigger a rebuild of
   // property trees as the effect node may no longer be needed.
@@ -10284,8 +10284,8 @@ TEST_F(LayerTreeHostCommonTest, PropertyTreesRebuildWithOpacityChanges) {
   EXPECT_TRUE(property_trees->needs_rebuild);
 
   ExecuteCalculateDrawPropertiesAndSaveUpdateLayerList(root.get());
-  EXPECT_EQ(property_trees->effect_id_to_index_map.find(child->id()),
-            property_trees->effect_id_to_index_map.end());
+  EXPECT_EQ(property_trees->layer_id_to_effect_node_index.find(child->id()),
+            property_trees->layer_id_to_effect_node_index.end());
 }
 
 TEST_F(LayerTreeHostCommonTest, OpacityAnimationsTrackingTest) {