Mac: Don't repaint scrollbars every frame

third_party/WebKit/Source/platform/exported/WebScrollbarThemeClientImpl.cpp

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 216 matching lines @@
 float WebScrollbarThemeClientImpl::elasticOverscroll() const
 {
     return m_scrollbar->elasticOverscroll();
 }
 
 void WebScrollbarThemeClientImpl::setElasticOverscroll(float elasticOverscroll)
 {
     return m_scrollbar->setElasticOverscroll(elasticOverscroll);
 }
 
+bool WebScrollbarThemeClientImpl::needsPaintTrack() const
+{
+    return true;
+}
+
+void WebScrollbarThemeClientImpl::setNeedsPaintTrack(bool)
+{
+    ASSERT_NOT_REACHED();
+}
+
+bool WebScrollbarThemeClientImpl::needsPaintThumb() const
+{
+    return true;
+}
+
+void WebScrollbarThemeClientImpl::setNeedsPaintThumb(bool)
+{
+    ASSERT_NOT_REACHED();
+}
+
 DisplayItemClient WebScrollbarThemeClientImpl::displayItemClient() const
 {
     ASSERT_NOT_REACHED();
     return toDisplayItemClient(this);
 }
 
 String WebScrollbarThemeClientImpl::debugName() const
 {
     return "WebScrollbarThemeClientImpl";
 }
 
 } // namespace blink