Replace layer id with Element id for tracking scrollbar animation controllers

cc/trees/layer_tree_host_unittest_context.cc

Index: cc/trees/layer_tree_host_unittest_context.cc
diff --git a/cc/trees/layer_tree_host_unittest_context.cc b/cc/trees/layer_tree_host_unittest_context.cc
index 3c7351f3ff466f4149f6731fcc506ea35b397164..56b4c57bb14c73384c7260c271594c7481d049b9 100644
--- a/cc/trees/layer_tree_host_unittest_context.cc
+++ b/cc/trees/layer_tree_host_unittest_context.cc
@@ -973,7 +973,8 @@ class LayerTreeHostContextTestDontUseLostResources
 
     scoped_refptr<PaintedScrollbarLayer> scrollbar =
         PaintedScrollbarLayer::Create(
-            std::unique_ptr<Scrollbar>(new FakeScrollbar), layer->id());
+            std::unique_ptr<Scrollbar>(new FakeScrollbar), layer->id(),
+            layer->element_id());
     scrollbar->SetBounds(gfx::Size(10, 10));
     scrollbar->SetIsDrawable(true);
     root->AddChild(scrollbar);
@@ -1088,8 +1089,8 @@ class ScrollbarLayerLostContext : public LayerTreeHostContextTest {
 
   void BeginTest() override {
     scoped_refptr<Layer> scroll_layer = Layer::Create();
-    scrollbar_layer_ =
-        FakePaintedScrollbarLayer::Create(false, true, scroll_layer->id());
+    scrollbar_layer_ = FakePaintedScrollbarLayer::Create(
+        false, true, scroll_layer->id(), scroll_layer->element_id());
     scrollbar_layer_->SetBounds(gfx::Size(10, 100));
     layer_tree_host()->root_layer()->AddChild(scrollbar_layer_);
     layer_tree_host()->root_layer()->AddChild(scroll_layer);