Made CSSPrimitiveValue::getString() only work for String types

Source/core/css/resolver/StyleBuilderCustom.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 2004-2005 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2006, 2007 Nicholas Shanks (webkit@nickshanks.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
  * Copyright (C) 2007, 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
@@ skipping 751 matching lines @@
             }
         }
     }
     if (!didSet)
         state.style()->clearContent();
 }
 
 void StyleBuilderFunctions::applyValueCSSPropertyWebkitLocale(StyleResolverState& state, CSSValue* value)
 {
     const CSSPrimitiveValue* primitiveValue = toCSSPrimitiveValue(value);
-    if (primitiveValue->getValueID() == CSSValueAuto)
+    if (primitiveValue->getValueID() == CSSValueAuto) {
         state.style()->setLocale(nullAtom);
-    else
+    } else {
+        ASSERT(primitiveValue->isString());
         state.style()->setLocale(AtomicString(primitiveValue->getStringValue()));
+    }
     state.fontBuilder().setScript(state.style()->locale());
 }
 
 void StyleBuilderFunctions::applyInitialCSSPropertyWebkitAppRegion(StyleResolverState&)
 {
 }
 
 void StyleBuilderFunctions::applyInheritCSSPropertyWebkitAppRegion(StyleResolverState&)
 {
 }
@@ skipping 44 matching lines @@
         return;
     case CSSValueSuper:
         svgStyle.setBaselineShift(BS_SUPER);
         return;
     default:
         ASSERT_NOT_REACHED();
     }
 }
 
 } // namespace blink