Add a hack to set shouldPaint to true for force-composited iframes.

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

 /*
  * Copyright (C) 2013 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 3299 matching lines @@
     if (isLayoutView()) {
         DoublePoint position = toLayoutView(this)->frameView()->scrollPositionDouble();
         adjustedLocation.move(position.x(), position.y());
     }
 
     const FloatingObjectSet& floatingObjectSet = m_floatingObjects->set();
     FloatingObjectSetIterator begin = floatingObjectSet.begin();
     for (FloatingObjectSetIterator it = floatingObjectSet.end(); it != begin;) {
         --it;
         const FloatingObject& floatingObject = *it->get();
-        if (floatingObject.shouldPaint() && !floatingObject.layoutObject()->hasSelfPaintingLayer()) {
+        if (floatingObject.shouldPaint()) {
             LayoutUnit xOffset = xPositionForFloatIncludingMargin(floatingObject) - floatingObject.layoutObject()->location().x();
             LayoutUnit yOffset = yPositionForFloatIncludingMargin(floatingObject) - floatingObject.layoutObject()->location().y();
             LayoutPoint childPoint = flipFloatForWritingModeForChild(floatingObject, adjustedLocation + LayoutSize(xOffset, yOffset));
             if (floatingObject.layoutObject()->hitTest(result, locationInContainer, childPoint)) {
                 updateHitTestResult(result, locationInContainer.point() - toLayoutSize(childPoint));
                 return true;
             }
         }
     }
 
@@ skipping 462 matching lines @@
     if (inlineElementContinuation)
         inlineElementContinuation->addOutlineRects(rects, additionalOffset + (inlineElementContinuation->containingBlock()->location() - location()), includeBlockOverflows);
 }
 
 PaintInvalidationReason LayoutBlockFlow::invalidatePaintIfNeeded(const PaintInvalidatorContext& context) const
 {
     return BlockFlowPaintInvalidator(*this, context).invalidatePaintIfNeeded();
 }
 
 } // namespace blink