Create a top-level "third_party" directory

This directory now contains third_party software that is vendored into
the Servo source tree. The idea is that it would eventually hold
webrender and other crates from mozilla-central as well with a standard
patch management approach for each.

third_party/WebIDL/tests/test_newobject.py

@@ -0,0 +1,76 @@
+# Import the WebIDL module, so we can do isinstance checks and whatnot
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    # Basic functionality
+    parser.parse(
+        """
+        interface Iface {
+          [NewObject] readonly attribute Iface attr;
+          [NewObject] Iface method();
+        };
+        """
+    )
+    results = parser.finish()
+    harness.ok(results, "Should not have thrown on basic [NewObject] usage")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface Iface {
+              [Pure, NewObject] readonly attribute Iface attr;
+            };
+            """
+        )
+        results = parser.finish()
+    except:
+        threw = True
+    harness.ok(threw, "[NewObject] attributes must depend on something")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface Iface {
+              [Pure, NewObject] Iface method();
+            };
+            """
+        )
+        results = parser.finish()
+    except:
+        threw = True
+    harness.ok(threw, "[NewObject] methods must depend on something")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface Iface {
+              [Cached, NewObject, Affects=Nothing] readonly attribute Iface attr;
+            };
+            """
+        )
+        results = parser.finish()
+    except:
+        threw = True
+    harness.ok(threw, "[NewObject] attributes must not be [Cached]")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface Iface {
+              [StoreInSlot, NewObject, Affects=Nothing] readonly attribute Iface attr;
+            };
+            """
+        )
+        results = parser.finish()
+    except:
+        threw = True
+    harness.ok(threw, "[NewObject] attributes must not be [StoreInSlot]")