Left side vertical MD scrollbars grow toward right.

cc/layers/painted_scrollbar_layer.cc

 // Copyright 2013 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/layers/painted_scrollbar_layer.h"
 
 #include <algorithm>
 
 #include "base/auto_reset.h"
 #include "cc/base/math_util.h"
 #include "cc/input/main_thread_scrolling_reason.h"
 #include "cc/layers/painted_scrollbar_layer_impl.h"
 #include "cc/resources/ui_resource_bitmap.h"
 #include "cc/trees/draw_property_utils.h"
 #include "cc/trees/layer_tree_host.h"
 #include "cc/trees/layer_tree_impl.h"
 #include "skia/ext/platform_canvas.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 #include "third_party/skia/include/core/SkSize.h"
 #include "ui/gfx/geometry/size_conversions.h"
 #include "ui/gfx/skia_util.h"
 
 namespace cc {
 
 std::unique_ptr<LayerImpl> PaintedScrollbarLayer::CreateLayerImpl(
     LayerTreeImpl* tree_impl) {
   return PaintedScrollbarLayerImpl::Create(
-      tree_impl, id(), scrollbar_->Orientation());
+      tree_impl, id(), scrollbar_->Orientation(),
+      scrollbar_->IsLeftSideVerticalScrollbar(), scrollbar_->IsOverlay());
 }
 
 scoped_refptr<PaintedScrollbarLayer> PaintedScrollbarLayer::Create(
     std::unique_ptr<Scrollbar> scrollbar,
     int scroll_layer_id) {
   return make_scoped_refptr(
       new PaintedScrollbarLayer(std::move(scrollbar), scroll_layer_id));
 }
 
 PaintedScrollbarLayer::PaintedScrollbarLayer(
@@ skipping 243 matching lines @@
 
   scrollbar_->PaintPart(&skcanvas, part, layer_rect);
   // Make sure that the pixels are no longer mutable to unavoid unnecessary
   // allocation and copying.
   skbitmap.setImmutable();
 
   return UIResourceBitmap(skbitmap);
 }
 
 }  // namespace cc