Remove scroll layer ids from scrollbar layers

cc/trees/layer_tree_host_unittest.cc

Index: cc/trees/layer_tree_host_unittest.cc
diff --git a/cc/trees/layer_tree_host_unittest.cc b/cc/trees/layer_tree_host_unittest.cc
index 39f7d49624125c8147570bbd8d6c2f78339bb4fb..acbd41b626f5cd2a2150cd1eba2d5692dd641b6f 100644
--- a/cc/trees/layer_tree_host_unittest.cc
+++ b/cc/trees/layer_tree_host_unittest.cc
@@ -1750,7 +1750,6 @@ class LayerTreeHostTestNoExtraCommitFromScrollbarInvalidate
     bool paint_scrollbar = true;
     bool has_thumb = false;
     scrollbar_ = FakePaintedScrollbarLayer::Create(paint_scrollbar, has_thumb,
-                                                   root_layer_->id(),
                                                    root_layer_->element_id());
     scrollbar_->SetPosition(gfx::PointF(0.f, 10.f));
     scrollbar_->SetBounds(gfx::Size(10, 10));
@@ -3738,7 +3737,7 @@ class LayerTreeHostTestPropertyChangesDuringUpdateArePushed
     bool paint_scrollbar = true;
     bool has_thumb = false;
     scrollbar_layer_ = FakePaintedScrollbarLayer::Create(
-        paint_scrollbar, has_thumb, root_->id(), root_->element_id());
+        paint_scrollbar, has_thumb, root_->element_id());
 
     root_->AddChild(scrollbar_layer_);