Bug 1066776. Make variadic dictionary arguments work. r=khuey

dom/bindings/parser/WebIDL.py

@@ -3405,6 +3405,7 @@ class IDLArgument(IDLObjectWithIdentifier):
         self._allowTreatNonCallableAsNull = False
 
         assert not variadic or optional
+        assert not variadic or not defaultValue
 
     def addExtendedAttributes(self, attrs):
         attrs = self.checkForStringHandlingExtendedAttributes(
@@ -3453,9 +3454,9 @@ class IDLArgument(IDLObjectWithIdentifier):
 
         if ((self.type.isDictionary() or
              self.type.isUnion() and self.type.unroll().hasDictionaryType) and
-            self.optional and not self.defaultValue):
-            # Default optional dictionaries to null, for simplicity,
-            # so the codegen doesn't have to special-case this.
+            self.optional and not self.defaultValue and not self.variadic):
+            # Default optional non-variadic dictionaries to null,
+            # for simplicity, so the codegen doesn't have to special-case this.
             self.defaultValue = IDLNullValue(self.location)
         elif self.type.isAny():
             assert (self.defaultValue is None or

dom/bindings/test/TestBindingHeader.h

@@ -714,6 +714,7 @@ public:
   void PassDictContainingDict(JSContext*, const DictContainingDict&);
   void PassDictContainingSequence(JSContext*, const DictContainingSequence&);
   void ReceiveDictContainingSequence(JSContext*, DictContainingSequence&);
+  void PassVariadicDictionary(JSContext*, const Sequence<Dict>&);
 
   // Typedefs
   void ExerciseTypedefInterfaces1(TestInterface&);

dom/bindings/test/TestCodeGen.webidl

@@ -686,6 +686,7 @@ interface TestInterface {
   void passDictContainingDict(optional DictContainingDict arg);
   void passDictContainingSequence(optional DictContainingSequence arg);
   DictContainingSequence receiveDictContainingSequence();
+  void passVariadicDictionary(Dict... arg);
 
   // EnforceRange/Clamp tests
   void dontEnforceRangeOrClamp(byte arg);

dom/bindings/test/TestExampleGen.webidl

@@ -550,6 +550,7 @@ interface TestExampleInterface {
   void passDictContainingDict(optional DictContainingDict arg);
   void passDictContainingSequence(optional DictContainingSequence arg);
   DictContainingSequence receiveDictContainingSequence();
+  void passVariadicDictionary(Dict... arg);
 
   // EnforceRange/Clamp tests
   void dontEnforceRangeOrClamp(byte arg);

dom/bindings/test/TestJSImplGen.webidl

@@ -566,6 +566,7 @@ interface TestJSImplInterface {
   void passDictContainingDict(optional DictContainingDict arg);
   void passDictContainingSequence(optional DictContainingSequence arg);
   DictContainingSequence receiveDictContainingSequence();
+  void passVariadicDictionary(Dict... arg);
 
   // EnforceRange/Clamp tests
   void dontEnforceRangeOrClamp(byte arg);