Replace hide-scrollbars flag with a web setting.

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 2d272212984fa06d25340d11c0945fca06af43f8..d7545e2403001c862882077846444ddb86bf6f71 100644
--- a/third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp
+++ b/third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp
@@ -1051,6 +1051,10 @@ void PaintLayerScrollableArea::setHasHorizontalScrollbar(bool hasScrollbar)
     if (FreezeScrollbarsScope::scrollbarsAreFrozen())
         return;
 
+    DCHECK(box().frame()->settings());
+    if (box().frame()->settings()->hideScrollbars())
+        hasScrollbar = false;
+
     if (hasScrollbar == hasHorizontalScrollbar())
         return;
 
@@ -1078,6 +1082,10 @@ void PaintLayerScrollableArea::setHasVerticalScrollbar(bool hasScrollbar)
     if (FreezeScrollbarsScope::scrollbarsAreFrozen())
         return;
 
+    DCHECK(box().frame()->settings());
+    if (box().frame()->settings()->hideScrollbars())
+        hasScrollbar = false;
+
     if (hasScrollbar == hasVerticalScrollbar())
         return;