Ensure we don't crash when asking for variables that don't exist from the computed style.

third_party/WebKit/Source/core/css/CSSComputedStyleDeclaration.cpp

 /*
  * Copyright (C) 2004 Zack Rusin <zack@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
  * Copyright (C) 2007 Nicholas Shanks <webkit@nickshanks.com>
  * Copyright (C) 2011 Sencha, Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
@@ skipping 623 matching lines @@
 
 CSSRule* CSSComputedStyleDeclaration::parentRule() const
 {
     return nullptr;
 }
 
 String CSSComputedStyleDeclaration::getPropertyValue(const String& propertyName)
 {
     CSSPropertyID propertyID = cssPropertyID(propertyName);
     if (!propertyID) {
-        if (!RuntimeEnabledFeatures::cssVariablesEnabled() || !CSSVariableParser::isValidVariableName(propertyName))
-            return String();
-        return getPropertyCSSValue(AtomicString(propertyName))->cssText();
+        if (RuntimeEnabledFeatures::cssVariablesEnabled() && CSSVariableParser::isValidVariableName(propertyName)) {
+            RefPtrWillBeRawPtr<CSSValue> value = getPropertyCSSValue(AtomicString(propertyName));
+            if (value)

[dstockwell, 2015/12/08 21:32:39]

indentation

[shans, 2015/12/08 21:49:25]

I think the indentation here is correct?

+                return value->cssText();
+        }
+        return String();
     }
     ASSERT(CSSPropertyMetadata::isEnabledProperty(propertyID));
     return getPropertyValue(propertyID);
 }
 
 String CSSComputedStyleDeclaration::getPropertyPriority(const String&)
 {
     // All computed styles have a priority of not "important".
     return "";
 }
@@ skipping 35 matching lines @@
     exceptionState.throwDOMException(NoModificationAllowedError, "These styles are computed, and therefore the '" + getPropertyNameString(id) + "' property is read-only.");
 }
 
 DEFINE_TRACE(CSSComputedStyleDeclaration)
 {
     visitor->trace(m_node);
     CSSStyleDeclaration::trace(visitor);
 }
 
 } // namespace blink