blink: Layers that have a backdrop-filter paints contents

Source/core/style/ComputedStyle.h

 /*
  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2003, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
@@ skipping 404 matching lines @@
 
     bool hasAppearance() const { return appearance() != NoControlPart; }
 
     bool isBackgroundColorCurrentColor() const { return backgroundColor().isCurrentColor() || visitedLinkBackgroundColor().isCurrentColor(); }
 
     bool hasBackground() const
     {
         Color color = visitedDependentColor(CSSPropertyBackgroundColor);
         if (color.alpha())
             return true;
-        return hasBackgroundImage();
+        return hasBackgroundImage() || hasBackdropFilter();

[pdr., 2015/09/04 22:42:13]

I think we need to return hasBackdropFilter from
hasBoxDecorationsOrBackgroundImage and maybe rename it?

BoxDecorationData also looks like it needs a hasBackdropFilter().

Basically, just search cs.chromium.org for hasBackgroundImage().

It would be great if we could test some of these places just to make sure we're
doing the right thing.

     }
 
     LayoutRectOutsets imageOutsets(const NinePieceImage&) const;
     bool hasBorderImageOutsets() const
     {
         return borderImage().hasImage() && borderImage().outset().nonZero();
     }
     LayoutRectOutsets borderImageOutsets() const
     {
         return imageOutsets(borderImage());
@@ skipping 1526 matching lines @@
 }
 
 inline bool ComputedStyle::hasPseudoElementStyle() const
 {
     return noninherited_flags.pseudoBits & PSEUDO_ELEMENT_MASK;
 }
 
 } // namespace blink
 
 #endif // ComputedStyle_h