Correct visual rects for scroll corner/resizer and non-frame composited scroll bars.

third_party/WebKit/Source/core/layout/LayoutScrollbarPart.cpp

 /*
  * Copyright (C) 2008 Apple 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 17 matching lines @@
 #include "core/frame/FrameView.h"
 #include "core/frame/UseCounter.h"
 #include "core/layout/LayoutScrollbar.h"
 #include "core/layout/LayoutScrollbarTheme.h"
 #include "core/layout/LayoutView.h"
 #include "core/paint/PaintLayerScrollableArea.h"
 #include "platform/LengthFunctions.h"
 
 namespace blink {
 
-LayoutScrollbarPart::LayoutScrollbarPart(LayoutScrollbar* scrollbar, ScrollbarPart part)
+LayoutScrollbarPart::LayoutScrollbarPart(ScrollableArea* scrollableArea, LayoutScrollbar* scrollbar, ScrollbarPart part)
     : LayoutBlock(nullptr)
+    , m_scrollableArea(scrollableArea)
     , m_scrollbar(scrollbar)
     , m_part(part)
 {
+    ASSERT(m_scrollableArea);
 }
 
 LayoutScrollbarPart::~LayoutScrollbarPart()
 {
 }
 
 static void recordScrollbarPartStats(Document& document, ScrollbarPart part)
 {
     switch (part) {
     case BackButtonStartPart:
@@ skipping 14 matching lines @@
         break;
     case ScrollbarBGPart:
         UseCounter::count(document, UseCounter::CSSSelectorPseudoScrollbar);
         break;
     case NoPart:
     case AllParts:
         break;
     }
 }
 
-LayoutScrollbarPart* LayoutScrollbarPart::createAnonymous(Document* document, LayoutScrollbar* scrollbar, ScrollbarPart part)
+LayoutScrollbarPart* LayoutScrollbarPart::createAnonymous(Document* document, ScrollableArea* scrollableArea,
+    LayoutScrollbar* scrollbar, ScrollbarPart part)
 {
-    LayoutScrollbarPart* layoutObject = new LayoutScrollbarPart(scrollbar, part);
+    LayoutScrollbarPart* layoutObject = new LayoutScrollbarPart(scrollableArea, scrollbar, part);
     recordScrollbarPartStats(*document, part);
     layoutObject->setDocumentForAnonymous(document);
     return layoutObject;
 }
 
 void LayoutScrollbarPart::layout()
 {
     setLocation(LayoutPoint()); // We don't worry about positioning ourselves. We're just determining our minimum width/height.
     if (m_scrollbar->orientation() == HorizontalScrollbar)
         layoutHorizontalPart();
@@ skipping 114 matching lines @@
 
     // This LayoutScrollbarPart is a scroll corner or a resizer.
     ASSERT(m_part == NoPart);
     if (FrameView* frameView = view()->frameView()) {
         if (frameView->isFrameViewScrollCorner(this)) {
             frameView->setScrollCornerNeedsPaintInvalidation();
             return;
         }
     }
 
-    // This LayoutScrollbarPart belongs to a PaintLayerScrollableArea.
-    toLayoutBox(parent())->getScrollableArea()->setScrollCornerNeedsPaintInvalidation();
+    m_scrollableArea->setScrollCornerNeedsPaintInvalidation();
 }
 
 LayoutRect LayoutScrollbarPart::visualRect() const
 {
     // This returns the combined bounds of all scrollbar parts, which is sufficient for correctness
     // but not as tight as it could be.
-    return m_scrollbar ? m_scrollbar->visualRect() : LayoutRect();
+    return m_scrollableArea->visualRectForScrollbarParts();
 }
 
 } // namespace blink