Bug 805871: Make PeerConnection constraints optional; r=jesup

dom/media/PeerConnection.js

@@ -268,6 +268,10 @@ PeerConnection.prototype = {
       throw new Error("createOffer already called");
     }
 
+    if (!constraints) {
+      constraints = {};
+    }
+
     if (!this._validateConstraints(constraints)) {
       throw new Error("createOffer passed invalid constraints");
     }
@@ -295,6 +299,10 @@ PeerConnection.prototype = {
       throw new Error("No outstanding offer");
     }
 
+    if (!constraints) {
+      constraints = {};
+    }
+
     if (!this._validateConstraints(constraints)) {
       throw new Error("createAnswer passed invalid constraints");
     }