Revert of Calculate paint invalidation rect for scrollbars

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

Index: third_party/WebKit/Source/core/layout/LayoutScrollbarPart.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutScrollbarPart.cpp b/third_party/WebKit/Source/core/layout/LayoutScrollbarPart.cpp
index 87294efd1a6af8d8c583f3bf12bb108dd8822061..0af88ce7cbfc9e4f9584c6c62475cbb79e0f4add 100644
--- a/third_party/WebKit/Source/core/layout/LayoutScrollbarPart.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutScrollbarPart.cpp
@@ -31,7 +31,6 @@
 #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 {
@@ -180,14 +179,24 @@
     clearPositionedState();
     setFloating(false);
     setHasOverflowClip(false);
-    if (oldStyle && (diff.needsPaintInvalidation() || diff.needsLayout()))
-        setNeedsPaintInvalidation();
+    if (oldStyle && m_scrollbar && m_part != NoPart && (diff.needsPaintInvalidation() || diff.needsLayout()))
+        m_scrollbar->theme()->invalidatePart(m_scrollbar, m_part);
 }
 
 void LayoutScrollbarPart::imageChanged(WrappedImagePtr image, const IntRect* rect)
 {
-    setNeedsPaintInvalidation();
-    LayoutBlock::imageChanged(image, rect);
+    if (m_scrollbar && m_part != NoPart) {
+        m_scrollbar->theme()->invalidatePart(m_scrollbar, m_part);
+    } else {
+        if (FrameView* frameView = view()->frameView()) {
+            if (frameView->isFrameViewScrollCorner(this)) {
+                frameView->invalidateScrollCorner(frameView->scrollCornerRect());
+                return;
+            }
+        }
+
+        LayoutBlock::imageChanged(image, rect);
+    }
 }
 
 LayoutObject* LayoutScrollbarPart::layoutObjectOwningScrollbar() const
@@ -195,24 +204,4 @@
     return (!m_scrollbar) ? nullptr : m_scrollbar->owningLayoutObject();
 }
 
-void LayoutScrollbarPart::setNeedsPaintInvalidation()
-{
-    if (m_scrollbar) {
-        m_scrollbar->setNeedsPaintInvalidation();
-        return;
-    }
-
-    // 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())->scrollableArea()->setScrollCornerNeedsPaintInvalidation();
-}
-
-}
+}