Add support for CSS unicod encoding to the text codec.

third_party/WebKit/Source/wtf/text/TextCodec.h

Index: third_party/WebKit/Source/wtf/text/TextCodec.h
diff --git a/third_party/WebKit/Source/wtf/text/TextCodec.h b/third_party/WebKit/Source/wtf/text/TextCodec.h
index 27e312858bd7bfe9743e3c32e96927c96b1946b3..1189e4e08deb3994e65a20001b0099173181c783 100644
--- a/third_party/WebKit/Source/wtf/text/TextCodec.h
+++ b/third_party/WebKit/Source/wtf/text/TextCodec.h
@@ -50,7 +50,11 @@ enum UnencodableHandling {
     // Encodes the character as en entity as above, but escaped
     // non-alphanumeric characters. This is used in URLs.
     // For example, U+6DE would be "%26%231758%3B".
-    URLEncodedEntitiesForUnencodables
+    URLEncodedEntitiesForUnencodables,
+
+    // Encodes the character as a CSS entity.  For example U+06DE
+    // would be \06de.  See: https://www.w3.org/TR/css-syntax-3/#escaping
+    CSSEncodedEntitiesForUnencodables,
 };
 
 typedef char UnencodableReplacementArray[32];