Remove scroll layer ids from scrollbar layers

cc/blink/web_scrollbar_layer_impl.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/blink/web_scrollbar_layer_impl.h"
 
 #include <utility>
 
 #include "base/memory/ptr_util.h"
 #include "cc/blink/scrollbar_impl.h"
@@ skipping 24 matching lines @@
 WebScrollbarLayerImpl::WebScrollbarLayerImpl(
     std::unique_ptr<blink::WebScrollbar> scrollbar,
     blink::WebScrollbarThemePainter painter,
     std::unique_ptr<blink::WebScrollbarThemeGeometry> geometry,
     bool is_overlay)
     : layer_(is_overlay
                  ? new WebLayerImpl(PaintedOverlayScrollbarLayer::Create(
                        base::MakeUnique<ScrollbarImpl>(std::move(scrollbar),
                                                        painter,
                                                        std::move(geometry)),
-                       cc::Layer::INVALID_ID,
                        cc::ElementId()))
                  : new WebLayerImpl(PaintedScrollbarLayer::Create(
                        base::MakeUnique<ScrollbarImpl>(std::move(scrollbar),
                                                        painter,
                                                        std::move(geometry)),
-                       cc::Layer::INVALID_ID,
                        cc::ElementId()))) {}
 
 WebScrollbarLayerImpl::WebScrollbarLayerImpl(
     blink::WebScrollbar::Orientation orientation,
     int thumb_thickness,
     int track_start,
     bool is_left_side_vertical_scrollbar)
     : layer_(new WebLayerImpl(
           SolidColorScrollbarLayer::Create(ConvertOrientation(orientation),
                                            thumb_thickness,
                                            track_start,
                                            is_left_side_vertical_scrollbar,
-                                           cc::Layer::INVALID_ID,
                                            cc::ElementId()))) {}
 
 WebScrollbarLayerImpl::~WebScrollbarLayerImpl() {
 }
 
 blink::WebLayer* WebScrollbarLayerImpl::Layer() {
   return layer_.get();
 }
 
 void WebScrollbarLayerImpl::SetScrollLayer(blink::WebLayer* layer) {
   cc::Layer* scroll_layer =
-      layer ? static_cast<WebLayerImpl*>(layer)->layer() : 0;
-  layer_->layer()->ToScrollbarLayer()->SetScrollInfo(
-      scroll_layer ? scroll_layer->id() : cc::Layer::INVALID_ID,
+      layer ? static_cast<WebLayerImpl*>(layer)->layer() : nullptr;
+  layer_->layer()->ToScrollbarLayer()->SetScrollElementId(
       scroll_layer ? scroll_layer->element_id() : cc::ElementId());
 }
 
 }  // namespace cc_blink