Hoist 7fd65affab as its own patch

components/script/dom/bindings/codegen/parser/bytestring.patch

@@ -0,0 +1,29 @@
+--- WebIDL.py
++++ WebIDL.py
+@@ -3391,6 +3391,11 @@ class IDLValue(IDLObject):
+             # extra normalization step.
+             assert self.type.isDOMString()
+             return self
++        elif self.type.isString() and type.isByteString():
++            # Allow ByteStrings to use default value just like
++            # DOMString.  No coercion is required here.
++            assert self.type.isDOMString()
++            return self
+         raise WebIDLError("Cannot coerce type %s to type %s." %
+                           (self.type, type), [location])
+
+@@ -5759,6 +5764,14 @@ class Parser(Tokenizer):
+         booleanType = BuiltinTypes[IDLBuiltinType.Types.boolean]
+         p[0] = IDLValue(location, booleanType, p[1])
+
++    def p_ConstValueByteString(self, p):
++        """
++            ConstValue : BYTESTRING
++        """
++        location = self.getLocation(p, 1)
++        bytestringType = BuiltinTypes[IDLBuiltinType.Types.bytestring]
++        p[0] = IDLValue(location, bytestringType, p[1])
++
+     def p_ConstValueInteger(self, p):
+         """
+             ConstValue : INTEGER

components/script/dom/bindings/codegen/parser/update.sh

@@ -3,6 +3,7 @@ patch < abstract.patch
 patch < debug.patch
 patch < pref-main-thread.patch
 patch < callback-location.patch
+patch < bytestring.patch
 
 wget https://hg.mozilla.org/mozilla-central/archive/tip.tar.gz/dom/bindings/parser/tests/ -O tests.tar.gz
 rm -r tests