Fix paint invalidation and painting for composited-scrolling input elements.

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 9237e04590abe81fc6949bfd8b2280c75224019d..caead6dd4c4a3a61d27520269078e1f0800ef183 100644
--- a/third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp
+++ b/third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp
@@ -1469,10 +1469,6 @@ void PaintLayerScrollableArea::updateCompositingLayersAfterScroll()
 
 bool PaintLayerScrollableArea::usesCompositedScrolling() const
 {
-    // Scroll form controls on the main thread so they exhibit correct touch scroll event bubbling
-    if (box().isIntrinsicallyScrollable(VerticalScrollbar) || box().isIntrinsicallyScrollable(HorizontalScrollbar))
-        return false;
-
     // See https://codereview.chromium.org/176633003/ for the tests that fail without this disabler.
     DisableCompositingQueryAsserts disabler;
     return layer()->hasCompositedLayerMapping() && layer()->compositedLayerMapping()->scrollingLayer();