Revert of Use element id's for animations

cc/animation/animation_host_perftest.cc

Index: cc/animation/animation_host_perftest.cc
diff --git a/cc/animation/animation_host_perftest.cc b/cc/animation/animation_host_perftest.cc
index a478a220a4713a4c93474c2e9efe3a9ba7ff953c..32b999b69f5b5ee9e9550d17a78c52a7fdc64146 100644
--- a/cc/animation/animation_host_perftest.cc
+++ b/cc/animation/animation_host_perftest.cc
@@ -62,14 +62,13 @@
     for (int i = 0; i < num_players; ++i) {
       scoped_refptr<Layer> layer = Layer::Create();
       root_layer_->AddChild(layer);
-      layer->SetElementId(LayerIdToElementIdForTesting(layer->id()));
 
       scoped_refptr<AnimationPlayer> player =
           AnimationPlayer::Create(last_player_id);
       last_player_id = AnimationIdProvider::NextPlayerId();
 
       timeline->AttachPlayer(player);
-      player->AttachElement(layer->element_id());
+      player->AttachElement(layer->id());
       EXPECT_TRUE(player->element_animations());
     }