[js] Skip silent profile installation step for Firefox

Mirrors changes made for

- java in 6fc17a0
- python/ruby in 9160eab

Author: jleyba

javascript/node/selenium-webdriver/CHANGES.md

@@ -24,6 +24,10 @@
 * FIXED: `remote.DriverService#start()` will now fail if the child process dies
     while waiting for the server to start accepting requests. Previously, start
     would continue to poll the server address until the timeout expired.
+* FIXED: Skip launching Firefox with the `-silent` flag to preheat the profile.
+    Starting with Firefox 38, this would cause the browser to crash. This step,
+    which was first introduced for Selenium's java client back with Firefox 2,
+    no longer appears to be required.
 * FIXED: 8564: `firefox.Driver#quit()` will wait for the Firefox process to
     terminate before deleting the temporary webdriver profile. This eliminates a
     race condition where Firefox would write profile data during shutdown,

javascript/node/selenium-webdriver/firefox/binary.js

@@ -132,28 +132,6 @@ function installNoFocusLibs(profileDir) {
 }
 
 
-/**
- * Silently runs Firefox to install a profile directory (which is assumed to be
- * defined in the given environment variables).
- * @param {string} firefox Path to the Firefox executable.
- * @param {!Object.<string, string>} env The environment variables to use.
- * @return {!promise.Promise} A promise for when the profile has been installed.
- */
-function installProfile(firefox, env) {
-  var installed = promise.defer();
-  child.exec(firefox + ' -silent', {env: env, timeout: 180 * 1000},
-      function(err) {
-        if (err) {
-          installed.reject(new Error(
-              'Failed to install Firefox profile: ' + err));
-          return;
-        }
-        installed.fulfill();
-      });
-  return installed.promise;
-}
-
-
 /**
  * Manages a Firefox subprocess configured for use with WebDriver.
  *
@@ -222,25 +200,13 @@ Binary.prototype.launch = function(profile) {
 
   var args = ['-foreground'].concat(this.args_);
 
-  var self = this;
-
   this.command_ = promise.when(this.exe_ || findFirefox(), function(firefox) {
     if (process.platform === 'win32' || process.platform === 'darwin') {
-      return firefox;
+      return exec(firefox, {args: args, env: env});
     }
     return installNoFocusLibs(profile).then(function(ldLibraryPath) {
       env['LD_LIBRARY_PATH'] = ldLibraryPath + ':' + env['LD_LIBRARY_PATH'];
       env['LD_PRELOAD'] = X_IGNORE_NO_FOCUS_LIB;
-      return firefox;
-    });
-  }).then(function(firefox) {
-    var install = exec(firefox, {args: ['-silent'], env: env});
-    return install.result().then(function(result) {
-      if (result.code !== 0) {
-        throw Error(
-            'Failed to install profile; firefox terminated with ' + result);
-      }
-
       return exec(firefox, {args: args, env: env});
     });
   });