Bug 1332122 - Remove unnecessary wrapper browser.startSession(). r=automatedtester

This wrapper just calls back into the MarionetteDriver, and
doesn't have any value. Removing it simplifies the call stack.

MozReview-Commit-ID: GH1xUHX12Xi

--HG--
extra : rebase_source : a3b9e57e63809c9936fdb2686ad6016339ea7bf7

testing/marionette/browser.js

@@ -234,11 +234,6 @@ browser.Context = class {
     });
   }
 
-  /** Called when we start a session with this browser. */
-  startSession(newSession, win, callback) {
-    callback(win, newSession);
-  }
-
   /**
    * Close the current tab.
    *

testing/marionette/driver.js

@@ -473,8 +473,7 @@ GeckoDriver.prototype.startBrowser = function(win, isNewSession = false) {
   this.curFrame = null;
   this.addBrowser(win);
   this.curBrowser.isNewSession = isNewSession;
-  this.curBrowser.startSession(
-      isNewSession, win, this.whenBrowserStarted.bind(this));
+  this.whenBrowserStarted(win, isNewSession);
 };
 
 /**
@@ -708,8 +707,9 @@ GeckoDriver.prototype.newSession = function* (cmd, resp) {
     waitForWindow.call(this);
   } else if (this.appName != "Firefox" && this.curBrowser === null) {
     // if there is a content listener, then we just wake it up
-    this.addBrowser(this.getCurrentWindow());
-    this.curBrowser.startSession(this.whenBrowserStarted.bind(this));
+    let win = this.getCurrentWindow();
+    this.addBrowser(win);
+    this.whenBrowserStarted(win, false);
     this.mm.broadcastAsyncMessage("Marionette:restart", {});
   } else {
     throw new WebDriverError("Session already running");