Improving the appearance of overlay scrollbars

ui/views/controls/scrollbar/cocoa_scroll_bar.mm

 // Copyright 2016 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.
 
 #import "ui/views/controls/scrollbar/cocoa_scroll_bar.h"
 
 #import "base/mac/sdk_forward_declarations.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "third_party/skia/include/effects/SkGradientShader.h"
 #include "ui/compositor/layer.h"
@@ skipping 190 matching lines @@
 
   gfx::Size track_size = local_bounds.size();
   track_size.SetToMax(GetThumb()->GetPreferredSize());
   local_bounds.set_size(track_size);
   return local_bounds;
 }
 
 //////////////////////////////////////////////////////////////////
 // CocoaScrollBar, ScrollBar:
 
-int CocoaScrollBar::GetLayoutSize() const {
-  return scroller_style_ == NSScrollerStyleOverlay ? 0 : ScrollbarThickness();
+int CocoaScrollBar::GetThickness() const {
+  return ScrollbarThickness();
 }
 
-int CocoaScrollBar::GetContentOverlapSize() const {
-  return scroller_style_ == NSScrollerStyleLegacy ? 0 : ScrollbarThickness();
+bool CocoaScrollBar::OverlapsContent() const {
+  return scroller_style_ == NSScrollerStyleOverlay;
 }
 
 //////////////////////////////////////////////////////////////////
 // CocoaScrollBar::View:
 
 void CocoaScrollBar::Layout() {
   // Set the thickness of the thumb according to the track bounds.
   // The length of the thumb is set by BaseScrollBar::Update().
   gfx::Rect thumb_bounds(GetThumb()->bounds());
   gfx::Rect track_bounds(GetTrackBounds());
@@ skipping 309 matching lines @@
 CocoaScrollBarThumb* CocoaScrollBar::GetCocoaScrollBarThumb() const {
   return static_cast<CocoaScrollBarThumb*>(GetThumb());
 }
 
 // static
 base::Timer* BaseScrollBar::GetHideTimerForTest(BaseScrollBar* scroll_bar) {
   return &static_cast<CocoaScrollBar*>(scroll_bar)->hide_scrollbar_timer_;
 }
 
 }  // namespace views