CSS.escape('\0') should not throw.

third_party/WebKit/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 193 matching lines @@
 {
     bool isFirst = true;
     bool isSecond = false;
     bool isFirstCharHyphen = false;
     unsigned index = 0;
     while (index < identifier.length()) {
         UChar32 c = identifier.characterStartingAt(index);
         if (c == 0) {
             // Check for lone surrogate which characterStartingAt does not return.
             c = identifier[index];
-            if (c == 0)
-                return false;

[Timothy Loh, 2015/12/03 04:08:03]

If this no longer returns false, we should just make the return type void and
remove the RaisesException attribute from the idl.

[ramya.v, 2015/12/03 06:33:46]

Done.

[ramya.v, 2015/12/03 06:33:46]

Made changes to return type.
RaisesException is used in case no arguments are provided to the escape method.
(From v8css.cpp  setMinimumArityTypeError(exceptionState, 1, info.Length());)

[Timothy Loh, 2015/12/03 07:16:51]

I checked and the code works without RaisesException.

         }
 
         index += U16_LENGTH(c);
 
         if (c <= 0x1f || c == 0x7f || (0x30 <= c && c <= 0x39 && (isFirst || (isSecond && isFirstCharHyphen))))
             serializeCharacterAsCodePoint(c, appendTo);
+        else if (c == 0)

[Timothy Loh, 2015/12/03 07:16:51]

Your code is returning \0 because the previous if statement will catch 0 and
we'll never get into the branch here.

+            serializeCharacterAsCodePoint(0xfffd, appendTo);
         else if (c == 0x2d && isFirst && index == identifier.length())
             serializeCharacter(c, appendTo);
         else if (0x80 <= c || c == 0x2d || c == 0x5f || (0x30 <= c && c <= 0x39) || (0x41 <= c && c <= 0x5a) || (0x61 <= c && c <= 0x7a))
             appendTo.append(c);
         else
             serializeCharacter(c, appendTo);
 
         if (isFirst) {
             isFirst = false;
             isSecond = true;
@@ skipping 30 matching lines @@
     serializeString(string, builder);
     return builder.toString();
 }
 
 String serializeURI(const String& string)
 {
     return "url(" + serializeString(string) + ")";
 }
 
 } // namespace blink