Change cc::ElementId to be a uint64_t

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 4da56d006490fdaf02502b7eaad583a205f1a658..116567ba16ba6af4e1b4e6889530716e20d9727d 100644
--- a/cc/animation/animation_host_perftest.cc
+++ b/cc/animation/animation_host_perftest.cc
@@ -67,7 +67,9 @@ class AnimationHostPerfTest : public testing::Test {
     for (int i = 0; i < num_players; ++i) {
       scoped_refptr<Layer> layer = Layer::Create();
       root_layer_->AddChild(layer);
-      layer->SetElementId(LayerIdToElementIdForTesting(layer->id()));
+      ElementId element_id;
+      element_id.id = layer->id();
+      layer->SetElementId(element_id);
 
       scoped_refptr<AnimationPlayer> player =
           AnimationPlayer::Create(last_player_id_);