Add commands to Chrome WebDriver for installing and manipulating extensions.

chrome/test/webdriver/test/chromedriver_factory.py

Index: chrome/test/webdriver/test/chromedriver_factory.py
diff --git a/chrome/test/webdriver/test/chromedriver_factory.py b/chrome/test/webdriver/test/chromedriver_factory.py
index 3f96947d402a1a9b0e18f881f1e217fdb6aac5f8..04dbfa5dd022951522a097ee24336c2bfee3b36f 100644
--- a/chrome/test/webdriver/test/chromedriver_factory.py
+++ b/chrome/test/webdriver/test/chromedriver_factory.py
@@ -5,10 +5,10 @@
 """Factory that creates ChromeDriver instances."""
 
 import copy
-from selenium.webdriver.remote.webdriver import WebDriver
+import chromedriver
 
 
-class WebDriverWrapper(WebDriver):
+class WebDriverWrapper(chromedriver.WebDriver):
   def __init__(self, executor, capabilities):
     super(WebDriverWrapper, self).__init__(executor, capabilities)
     self._did_quit = False