Bug 1225563 - Log error in JS that Doorhangers only support one positive and one negative button if invalid buttons are provided. r=nalexander

mobile/android/chrome/content/browser.js

@@ -2283,6 +2283,11 @@ var NativeWindow = {
         aButtons = [];
       }
 
+      if (aButtons.length > 2) {
+        console.log("Doorhanger can have a maximum of two buttons!");
+        aButtons.length = 2;
+      }
+
       aButtons.forEach((function(aButton) {
         this._callbacks[this._callbacksId] = { cb: aButton.callback, prompt: this._promptId };
         aButton.callback = this._callbacksId;