Reduce CSSProperty's StylePropertyMetadata memory footprint by half when used inside a ImmutableSty…

Source/core/css/CSSProperty.cpp

 /**
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2005, 2006 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.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 19 matching lines @@
 
 namespace WebCore {
 
 struct SameSizeAsCSSProperty {
     uint32_t bitfields;
     void* value;
 };
 
 COMPILE_ASSERT(sizeof(CSSProperty) == sizeof(SameSizeAsCSSProperty), CSSProperty_should_stay_small);
 
+CSSPropertyID StylePropertyMetadata::shorthandID() const
+{
+    if (!m_isSetFromShorthand)
+        return CSSPropertyInvalid;
+
+    const Vector<StylePropertyShorthand> shorthands = matchingShorthandsForLonghand(static_cast<CSSPropertyID>(m_propertyID));
+    ASSERT(shorthands.size());
+    if (shorthands.size() > 1) {

[Julien - ping for review, 2013/06/14 17:38:27]

Do we really need this branch? m_shorthandID is 0 by default so it seems that we
don't need it.

+        ASSERT(m_shorthandID >= 0 && m_shorthandID < shorthands.size());
+        return shorthands.at(m_shorthandID).id();
+    }
+    return shorthands.at(0).id();
+}
+
 void CSSProperty::wrapValueInCommaSeparatedList()
 {
     RefPtr<CSSValue> value = m_value.release();
     m_value = CSSValueList::createCommaSeparated();
     toCSSValueList(m_value.get())->append(value.release());
 }
 
 enum LogicalBoxSide { BeforeSide, EndSide, AfterSide, StartSide };
 enum PhysicalBoxSide { TopSide, RightSide, BottomSide, LeftSide };
 
@@ skipping 107 matching lines @@
 static CSSPropertyID resolveToPhysicalProperty(WritingMode writingMode, LogicalExtent logicalSide, const CSSPropertyID* properties)
 {
     if (writingMode == TopToBottomWritingMode || writingMode == BottomToTopWritingMode)
         return properties[logicalSide];
     return logicalSide == LogicalWidth ? properties[1] : properties[0];
 }
 
 static const StylePropertyShorthand& borderDirections()
 {
     static const CSSPropertyID properties[4] = { CSSPropertyBorderTop, CSSPropertyBorderRight, CSSPropertyBorderBottom, CSSPropertyBorderLeft };
-    DEFINE_STATIC_LOCAL(StylePropertyShorthand, borderDirections, (properties, WTF_ARRAY_LENGTH(properties)));
+    DEFINE_STATIC_LOCAL(StylePropertyShorthand, borderDirections, (CSSPropertyBorder, properties, WTF_ARRAY_LENGTH(properties)));
     return borderDirections;
 }
 
 CSSPropertyID CSSProperty::resolveDirectionAwareProperty(CSSPropertyID propertyID, TextDirection direction, WritingMode writingMode)
 {
     switch (propertyID) {
     case CSSPropertyWebkitMarginEnd:
         return resolveToPhysicalProperty(direction, writingMode, EndSide, marginShorthand());
     case CSSPropertyWebkitMarginStart:
         return resolveToPhysicalProperty(direction, writingMode, StartSide, marginShorthand());
@@ skipping 494 matching lines @@
 }
 
 void CSSProperty::reportMemoryUsage(MemoryObjectInfo* memoryObjectInfo) const
 {
     MemoryClassInfo info(memoryObjectInfo, this, WebCoreMemoryTypes::CSS);
     info.addMember(m_value, "value");
     info.ignoreMember(m_metadata);
 }
 
 } // namespace WebCore