BackgroundImage incorrectly returns empty url() when created on-the-fly

Source/core/css/CSSMarkup.cpp

 /*
  * Copyright (C) 2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Nicholas Shanks <webkit@nickshanks.com>
  * Copyright (C) 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2012 Adobe Systems Incorporated. All rights reserved.
  * Copyright (C) 2012 Intel Corporation. All rights reserved.
  *
@@ skipping 245 matching lines @@
     appendTo.append('\"');
 }
 
 String serializeString(const String& string)
 {
     StringBuilder builder;
     serializeString(string, builder);
     return builder.toString();
 }
 
+String serializeStringWithoutQuotations(const String& string)
+{
+    StringBuilder appendTo;
+    unsigned index = 0;
+    while (index < string.length()) {
+        UChar32 c = string.characterStartingAt(index);
+        index += U16_LENGTH(c);
+        if (c <= 0x1f)
+            serializeCharacterAsCodePoint(c, appendTo);
+        else if (c == 0x22 || c == 0x5c)
+            serializeCharacter(c, appendTo);
+        else
+            appendTo.append(c);
+    }
+    return appendTo.toString();
+}
+
 } // namespace blink