Bug 923607 - Suppress safe-mode dialog when starting in safe-mode; r=automatedtester

testing/marionette/components/marionettecomponent.js

@@ -93,6 +93,12 @@ MarionetteComponent.prototype = {
         if (enabledPref) {
           this.enabled = true;
           this.logger.info("marionette enabled via build flag and pref");
+
+          // We want to suppress the modal dialog that's shown
+          // when starting up in safe-mode to enable testing.
+          if (Services.appinfo.inSafeMode) {
+            this.observerService.addObserver(this, "domwindowopened", false);
+          }
         }
         else {
           this.logger.info("marionette not enabled via pref");
@@ -105,6 +111,10 @@ MarionetteComponent.prototype = {
         this.observerService.addObserver(this, "xpcom-shutdown", false);
         this.init();
         break;
+      case "domwindowopened":
+        this.observerService.removeObserver(this, aTopic);
+        this._suppressSafeModeDialog(aSubject);
+        break;
       case "xpcom-shutdown":
         this.observerService.removeObserver(this, "xpcom-shutdown");
         this.uninit();
@@ -112,6 +122,20 @@ MarionetteComponent.prototype = {
     }
   },
 
+  _suppressSafeModeDialog: function mc_suppressSafeModeDialog(aWindow) {
+    // Wait for the modal dialog to finish loading.
+    aWindow.addEventListener("load", function onLoad() {
+      aWindow.removeEventListener("load", onLoad);
+
+      if (aWindow.document.getElementById("safeModeDialog")) {
+        aWindow.setTimeout(() => {
+          // Accept the dialog to start in safe-mode.
+          aWindow.document.documentElement.getButton("accept").click();
+        });
+      }
+    });
+  },
+
   init: function mc_init() {
     if (!this._loaded && this.enabled && this.finalUiStartup) {
       this._loaded = true;