Set scrollbar enabled state for overflow:auto.

third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp

Index: third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp
diff --git a/third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp b/third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp
index 88711260d5bea2d9fc0e4c43a1a5fdd2fbc13586..51cfc57ab6a896545d4ea5b9ec14136a3ff77154 100644
--- a/third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp
+++ b/third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp
@@ -657,16 +657,13 @@ void PaintLayerScrollableArea::updateScrollDimensions() {
 }
 
 void PaintLayerScrollableArea::updateScrollbarEnabledState() {
-  bool forceDisabled = ScrollbarTheme::theme().disableInvisibleScrollbars() &&
-                       scrollbarsHidden();
-  // overflow:scroll should just enable/disable.
-  if (box().style()->overflowX() == OverflowScroll && horizontalScrollbar()) {
-    horizontalScrollbar()->setEnabled(hasHorizontalOverflow() &&
-                                      !forceDisabled);
-  }
-  if (box().style()->overflowY() == OverflowScroll && verticalScrollbar()) {
-    verticalScrollbar()->setEnabled(hasVerticalOverflow() && !forceDisabled);
-  }
+  bool forceDisable = ScrollbarTheme::theme().disableInvisibleScrollbars() &&
+                      scrollbarsHidden();
+
+  if (horizontalScrollbar())
+    horizontalScrollbar()->setEnabled(hasHorizontalOverflow() && !forceDisable);
+  if (verticalScrollbar())
+    verticalScrollbar()->setEnabled(hasVerticalOverflow() && !forceDisable);
 }
 
 void PaintLayerScrollableArea::setScrollOffsetUnconditionally(