feat(webdriver): Allow users to use webdriver's disableEnvironmentOverrides

Fixes #2300

Author: Alexander Albul

docs/referenceConf.js

@@ -340,5 +340,10 @@ exports.config = {
 
   // Turns off source map support.  Stops protractor from registering global
   // variable `source-map-support`.  Defaults to `false`
-  skipSourceMapSupport: false
+  skipSourceMapSupport: false,
+
+  // Turns off WebDriver's environment variables overrides to ignore any
+  // environment variable and to only use the configuration in this file.
+  // Defaults to `true`
+  environmentOverrides: true
 };

lib/driverProviders/driverProvider.js

@@ -32,10 +32,13 @@ DriverProvider.prototype.getExistingDrivers = function() {
  * @return webdriver instance
  */
 DriverProvider.prototype.getNewDriver = function() {
-  var newDriver = new webdriver.Builder().
-      usingServer(this.config_.seleniumAddress).
-      withCapabilities(this.config_.capabilities).
-      build();
+  var builder = new webdriver.Builder().
+    usingServer(this.config_.seleniumAddress).
+    withCapabilities(this.config_.capabilities);
+  if (this.config_.environmentOverrides === false) {
+    builder.disableEnvironmentOverrides();
+  }
+  var newDriver = builder.build();
   this.drivers_.push(newDriver);
   return newDriver;
 };