Reduce the number of CachedUAStyles

Source/core/rendering/RenderTheme.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 68 matching lines @@
 }
 
 RenderTheme::RenderTheme()
     : m_hasCustomFocusRingColor(false)
 #if USE(NEW_THEME)
     , m_platformTheme(platformTheme())
 #endif
 {
 }
 
-void RenderTheme::adjustStyle(RenderStyle* style, Element* e, const CachedUAStyle& uaStyle)
+void RenderTheme::adjustStyle(RenderStyle* style, Element* e, const CachedUAStyle* 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.hasAppearance && isControlStyled(style, uaStyle)) {
+    if (uaStyle && uaStyle->hasAppearance && isControlStyled(style, uaStyle)) {
         if (part == MenulistPart) {
             style->setAppearance(MenulistButtonPart);
             part = MenulistButtonPart;
         } else
             style->setAppearance(NoControlPart);
     }
 
     if (!style->hasAppearance())
         return;
 
@@ skipping 449 matching lines @@
     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 RenderTheme::isControlStyled(const RenderStyle* style, const CachedUAStyle& uaStyle) const
+bool RenderTheme::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 isBackgroundOrBorderStyled(*style, *uaStyle);
 
     case ListboxPart:
     case MenulistPart:
     case SearchFieldPart:
     case TextAreaPart:
     case TextFieldPart:
-        return isBackgroundOrBorderStyled(*style, uaStyle) || style->boxShadow();
+        return isBackgroundOrBorderStyled(*style, *uaStyle) || style->boxShadow();
 
     case SliderHorizontalPart:
     case SliderVerticalPart:
         return style->boxShadow();
 
     default:
         return false;
     }
 }
 
@@ skipping 615 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 WebCore