Let StyleResolver figure out differences between UA style and resolved style.

Source/core/layout/LayoutThemeChromiumMac.mm

 /*
  * Copyright (C) 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Google, Inc.
  *
  * 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
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 24 matching lines @@
 #import "core/html/shadow/MediaControlElements.h"
 #import "core/layout/LayoutSlider.h"
 #import "core/rendering/PaintInfo.h"
 #import "core/rendering/RenderLayer.h"
 #import "core/rendering/RenderMedia.h"
 #import "core/rendering/RenderMediaControls.h"
 #import "core/rendering/RenderMeter.h"
 #import "core/rendering/RenderProgress.h"
 #import "core/rendering/RenderView.h"
 #import "core/rendering/style/ShadowList.h"
+#import "core/rendering/style/UAStyleChange.h"
 #import "platform/LayoutTestSupport.h"
 #import "platform/PlatformResourceLoader.h"
 #import "platform/SharedBuffer.h"
 #import "platform/geometry/FloatRoundedRect.h"
 #import "platform/graphics/BitmapImage.h"
 #import "platform/graphics/GraphicsContextStateSaver.h"
 #import "platform/graphics/Image.h"
 #import "platform/graphics/ImageBuffer.h"
 #import "platform/mac/ColorMac.h"
 #import "platform/mac/LocalCurrentGraphicsContext.h"
@@ skipping 407 matching lines @@
     }
 
     if (needsFallback)
         color = LayoutTheme::systemColor(cssValueId);
 
     m_systemColorCache.set(cssValueId, color.rgb());
 
     return color;
 }
 
-bool LayoutThemeChromiumMac::isControlStyled(const RenderStyle* style, const CachedUAStyle* uaStyle) const
+bool LayoutThemeChromiumMac::isControlStyled(const RenderStyle* style, const UAStyleChange& uaStyle) const
 {
-    ASSERT(uaStyle);
     if (style->appearance() == TextFieldPart || style->appearance() == TextAreaPart)
-        return style->border() != uaStyle->border || style->boxShadow();
+        return uaStyle.borderChanged || style->boxShadow();
 
     // FIXME: This is horrible, but there is not much else that can be done.
     // Menu lists cannot draw properly when scaled. They can't really draw
     // properly when transformed either. We can't detect the transform case at
     // style adjustment time so that will just have to stay broken.  We can
     // however detect that we're zooming. If zooming is in effect we treat it
     // like the control is styled.
     if (style->appearance() == MenulistPart && style->effectiveZoom() != 1.0f)
         return true;
     // FIXME: NSSearchFieldCell doesn't work well when scaled.
@@ skipping 1357 matching lines @@
 
 bool LayoutThemeChromiumMac::shouldUseFallbackTheme(RenderStyle* style) const
 {
     ControlPart part = style->appearance();
     if (part == CheckboxPart || part == RadioPart)
         return style->effectiveZoom() != 1;
     return false;
 }
 
 } // namespace blink