Bug 978143 - Propagate APK install cancellation back to webpage. r=wesj

mobile/android/base/webapp/EventListener.java

@@ -183,7 +183,7 @@ public class EventListener implements NativeEventListener  {
         }
     }
 
-    public static void installApk(final Activity context, NativeJSObject message, EventCallback callback) {
+    public static void installApk(final Activity context, NativeJSObject message, final EventCallback callback) {
         final JSONObject messageData;
 
         // We get the manifest url out of javascript here so we can use it as a checksum
@@ -237,6 +237,7 @@ public class EventListener implements NativeEventListener  {
                         // unregistered the receiver).
                         Log.e(LOGTAG, "error unregistering install receiver: ", e);
                     }
+                    callback.sendError("APK installation cancelled by user");
                 }
             }
         });

mobile/android/modules/WebappManager.jsm

@@ -500,6 +500,12 @@ this.WebappManager = {
           type: "Webapps:InstallApk",
           filePath: apk.filePath,
           data: msg,
+        }, (data, error) => {
+          if (!!error) {
+            // There's no page to report back to so drop the error.
+            // TODO: we should notify the user about this failure.
+            debug("APK install failed : " + returnError);
+          }
         });
       }
     } else {