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

Source/core/layout/LayoutTheme.cpp

 /**
  * This file is part of the theme implementation for form controls in WebCore.
  *
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2012 Apple Computer, 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.
  *
@@ skipping 31 matching lines @@
 #include "core/html/shadow/MediaControlElements.h"
 #include "core/html/shadow/ShadowElementNames.h"
 #include "core/html/shadow/SpinButtonElement.h"
 #include "core/html/shadow/TextControlInnerElements.h"
 #include "core/page/FocusController.h"
 #include "core/page/Page.h"
 #include "core/rendering/PaintInfo.h"
 #include "core/rendering/RenderMeter.h"
 #include "core/rendering/RenderView.h"
 #include "core/rendering/style/RenderStyle.h"
+#include "core/rendering/style/UAStyleChange.h"
 #include "platform/FileMetadata.h"
 #include "platform/FloatConversion.h"
 #include "platform/RuntimeEnabledFeatures.h"
 #include "platform/fonts/FontSelector.h"
 #include "platform/graphics/GraphicsContextStateSaver.h"
 #include "platform/text/PlatformLocale.h"
 #include "platform/text/StringTruncator.h"
 #include "public/platform/Platform.h"
 #include "public/platform/WebFallbackThemeEngine.h"
 #include "public/platform/WebRect.h"
@@ skipping 18 matching lines @@
 }
 
 LayoutTheme::LayoutTheme()
     : m_hasCustomFocusRingColor(false)
 #if USE(NEW_THEME)
     , m_platformTheme(platformTheme())
 #endif
 {
 }
 
-void LayoutTheme::adjustStyle(RenderStyle* style, Element* e, const CachedUAStyle* uaStyle)
+void LayoutTheme::adjustStyle(RenderStyle* style, Element* e, const UAStyleChange& uaStyle)
 {
     // Force inline and table display styles to be inline-block (except for table- which is block)
     ControlPart part = style->appearance();
     if (style->display() == INLINE || style->display() == INLINE_TABLE || style->display() == TABLE_ROW_GROUP
         || style->display() == TABLE_HEADER_GROUP || style->display() == TABLE_FOOTER_GROUP
         || style->display() == TABLE_ROW || style->display() == TABLE_COLUMN_GROUP || style->display() == TABLE_COLUMN
         || style->display() == TABLE_CELL || style->display() == TABLE_CAPTION)
         style->setDisplay(INLINE_BLOCK);
     else if (style->display() == LIST_ITEM || style->display() == TABLE)
         style->setDisplay(BLOCK);
 
-    if (uaStyle && isControlStyled(style, uaStyle)) {
+    if (uaStyle.hasAppearance && isControlStyled(style, uaStyle)) {
         if (part == MenulistPart) {
             style->setAppearance(MenulistButtonPart);
             part = MenulistButtonPart;
         } else {
             style->setAppearance(NoControlPart);
         }
     }
 
     if (!style->hasAppearance())
         return;
@@ skipping 425 matching lines @@
 #endif
 }
 
 bool LayoutTheme::isControlContainer(ControlPart appearance) const
 {
     // There are more leaves than this, but we'll patch this function as we add support for
     // more controls.
     return appearance != CheckboxPart && appearance != RadioPart;
 }
 
-static bool isBackgroundOrBorderStyled(const RenderStyle& style, const CachedUAStyle& uaStyle)
+bool LayoutTheme::isControlStyled(const RenderStyle* style, const UAStyleChange& uaStyle) const
 {
-    // Code below excludes the background-repeat from comparison by resetting it
-    FillLayer backgroundCopy = uaStyle.backgroundLayers;
-    FillLayer backgroundLayersCopy = style.backgroundLayers();
-    backgroundCopy.setRepeatX(NoRepeatFill);
-    backgroundCopy.setRepeatY(NoRepeatFill);
-    backgroundLayersCopy.setRepeatX(NoRepeatFill);
-    backgroundLayersCopy.setRepeatY(NoRepeatFill);
-    // Test the style to see if the UA border and background match.
-    return style.border() != uaStyle.border
-        || backgroundLayersCopy != backgroundCopy
-        || style.visitedDependentColor(CSSPropertyBackgroundColor) != uaStyle.backgroundColor;
-}
-
-bool LayoutTheme::isControlStyled(const RenderStyle* style, const CachedUAStyle* uaStyle) const
-{
-    ASSERT(uaStyle);
-
     switch (style->appearance()) {
     case PushButtonPart:
     case SquareButtonPart:
     case ButtonPart:
     case ProgressBarPart:
     case MeterPart:
     case RelevancyLevelIndicatorPart:
     case ContinuousCapacityLevelIndicatorPart:
     case DiscreteCapacityLevelIndicatorPart:
     case RatingLevelIndicatorPart:
-        return isBackgroundOrBorderStyled(*style, *uaStyle);
+        return uaStyle.backgroundChanged || uaStyle.borderChanged;
 
     case MenulistPart:
     case SearchFieldPart:
     case TextAreaPart:
     case TextFieldPart:
-        return isBackgroundOrBorderStyled(*style, *uaStyle) || style->boxShadow();
+        return uaStyle.backgroundChanged || uaStyle.borderChanged || style->boxShadow();
 
     case SliderHorizontalPart:
     case SliderVerticalPart:
         return style->boxShadow();
 
     default:
         return false;
     }
 }
 
@@ skipping 664 matching lines @@
 
     // padding - not honored by WinIE, needs to be removed.
     style->resetPadding();
 
     // border - honored by WinIE, but looks terrible (just paints in the control box and turns off the Windows XP theme)
     // for now, we will not honor it.
     style->resetBorder();
 }
 
 } // namespace blink