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

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

Index: third_party/WebKit/Source/core/css/CSSMarkup.cpp
diff --git a/third_party/WebKit/Source/core/css/CSSMarkup.cpp b/third_party/WebKit/Source/core/css/CSSMarkup.cpp
index 7c5e890579db48b3c997dffb425a2d0530aeaaf0..670f6d834ea941fe84000fd481fef549be59878a 100644
--- a/third_party/WebKit/Source/core/css/CSSMarkup.cpp
+++ b/third_party/WebKit/Source/core/css/CSSMarkup.cpp
@@ -211,14 +211,14 @@ bool serializeIdentifier(const String& identifier, StringBuilder& appendTo)
         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))