Bug 826146 - Add a pref-controlled install confirmation override for automation. r=sicking

dom/apps/src/Webapps.jsm

@@ -1382,9 +1382,17 @@ this.DOMApplicationRegistry = {
           sendError("INVALID_SECURITY_LEVEL");
         } else {
           app.etag = xhr.getResponseHeader("Etag");
+          // We allow bypassing the install confirmation process to facilitate
+          // automation.
+          let prefName = "dom.mozApps.auto_confirm_install";
+          if (Services.prefs.prefHasUserValue(prefName) &&
+              Services.prefs.getBoolPref(prefName)) {
+            this.confirmInstall(aData);
+          } else {
             Services.obs.notifyObservers(aMm, "webapps-ask-install",
                                          JSON.stringify(aData));
           }
+        }
       } else {
         sendError("MANIFEST_URL_ERROR");
       }

testing/specialpowers/content/specialpowersAPI.js

@@ -713,6 +713,14 @@ SpecialPowersAPI.prototype = {
     }
   },
 
+  // Disables the app install prompt for the duration of this test. There is
+  // no need to re-enable the prompt at the end of the test.
+  //
+  // The provided callback is invoked once the prompt is disabled.
+  autoConfirmAppInstall: function(cb) {
+    this.pushPrefEnv({set: [['dom.mozApps.auto_confirm_install', true]]}, cb);
+  },
+
   addObserver: function(obs, notification, weak) {
     var obsvc = Cc['@mozilla.org/observer-service;1']
                    .getService(Ci.nsIObserverService);