Change cc::ElementId to be a uint64_t

cc/input/single_scrollbar_animation_controller_thinning_unittest.cc

Index: cc/input/single_scrollbar_animation_controller_thinning_unittest.cc
diff --git a/cc/input/single_scrollbar_animation_controller_thinning_unittest.cc b/cc/input/single_scrollbar_animation_controller_thinning_unittest.cc
index 0faa8d3265bd0134ab5cfeef7bf29dde7eb42398..34a8466e6c31e615242b9b3f1c678898ad478c93 100644
--- a/cc/input/single_scrollbar_animation_controller_thinning_unittest.cc
+++ b/cc/input/single_scrollbar_animation_controller_thinning_unittest.cc
@@ -67,8 +67,9 @@ class SingleScrollbarAnimationControllerThinningTest : public testing::Test {
         LayerImpl::Create(host_impl_.active_tree(), 1);
     std::unique_ptr<LayerImpl> clip =
         LayerImpl::Create(host_impl_.active_tree(), 3);
-    scroll_layer->SetElementId(
-        LayerIdToElementIdForTesting(scroll_layer->id()));
+    ElementId element_id;
+    element_id.id = scroll_layer->id();
+    scroll_layer->SetElementId(element_id);
     clip_layer_ = clip.get();
     scroll_layer->SetScrollClipLayer(clip_layer_->id());
     LayerImpl* scroll_layer_ptr = scroll_layer.get();