Use StyleBuilderConverter for [-webkit-]perspective.

Source/core/css/resolver/StyleBuilderConverter.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
  * copyright notice, this list of conditions and the following disclaimer
  * in the documentation and/or other materials provided with the
  * distribution.
  *     * Neither the name of Google Inc. nor the names of its
@@ skipping 567 matching lines @@
 
 float StyleBuilderConverter::convertNumberOrPercentage(StyleResolverState& state, CSSValue* value)
 {
     CSSPrimitiveValue* primitiveValue = toCSSPrimitiveValue(value);
     ASSERT(primitiveValue->isNumber() || primitiveValue->isPercentage());
     if (primitiveValue->isNumber())
         return primitiveValue->getFloatValue();
     return primitiveValue->getFloatValue() / 100.0f;
 }
 
+static float convertPerspectiveLength(StyleResolverState& state, CSSPrimitiveValue* primitiveValue)
+{
+    return std::max(primitiveValue->computeLength<float>(state.cssToLengthConversionData()), 0.0f);
+}
+
+float StyleBuilderConverter::convertPerspective(StyleResolverState& state, CSSValue* value)
+{
+    CSSPrimitiveValue* primitiveValue = toCSSPrimitiveValue(value);
+
+    if (primitiveValue->getValueID() == CSSValueNone)
+        return RenderStyle::initialPerspective();
+
+    // CSSPropertyWebkitPerspective accepts unitless numbers.
+    if (primitiveValue->isNumber()) {
+        RefPtr<CSSPrimitiveValue> px = CSSPrimitiveValue::create(primitiveValue->getDoubleValue(), CSSPrimitiveValue::CSS_PX);
+        return convertPerspectiveLength(state, px.get());
+    }
+
+    return convertPerspectiveLength(state, primitiveValue);
+}
+
 EPaintOrder StyleBuilderConverter::convertPaintOrder(StyleResolverState&, CSSValue* cssPaintOrder)
 {
     if (cssPaintOrder->isValueList()) {
         int paintOrder = 0;
         const CSSValueList& list = *toCSSValueList(cssPaintOrder);
         for (size_t i = 0; i < list.length(); ++i) {
             EPaintOrderType paintOrderType = PT_NONE;
             switch (toCSSPrimitiveValue(list.item(i))->getValueID()) {
             case CSSValueFill:
                 paintOrderType = PT_FILL;
@@ skipping 132 matching lines @@
 {
     CSSPrimitiveValue* primitiveValue = toCSSPrimitiveValue(value);
     if (primitiveValue->getValueID()) {
         float multiplier = convertLineWidth<float>(state, value);
         return CSSPrimitiveValue::create(multiplier / 48, CSSPrimitiveValue::CSS_EMS)->computeLength<float>(state.cssToLengthConversionData());
     }
     return primitiveValue->computeLength<float>(state.cssToLengthConversionData());
 }
 
 } // namespace blink