Update ChromeDriver to accept W3C format InitSession

chrome/test/chromedriver/test/run_py_tests.py

Index: chrome/test/chromedriver/test/run_py_tests.py
diff --git a/chrome/test/chromedriver/test/run_py_tests.py b/chrome/test/chromedriver/test/run_py_tests.py
index 88019e909757ef235bac54e2c91251f41eaafb7b..0956cff8dd1cba63c8e39d81a955774ffc196dd6 100755
--- a/chrome/test/chromedriver/test/run_py_tests.py
+++ b/chrome/test/chromedriver/test/run_py_tests.py
@@ -2125,15 +2125,16 @@ class MobileEmulationCapabilityTest(ChromeDriverBaseTest):
     self.assertEquals(network, connection_type)
 
   def testW3cCompliantResponses(self):
-    # Asserts that chromedriver has received the correct response.
-    # W3C compliant responses should only be received when the capability has
-    # been set and the request was sent in the correct format.
-    driver = self.CreateDriver(send_w3c_request=True)
-    self.assertFalse(driver.w3c_compliant)
+    # It's an error to send w3c format request without w3c capability flag.

[samuong, 2017/03/29 17:07:48]

nit: w3c -> W3C

+    with self.assertRaises(chromedriver.UnknownError):
+      self.CreateDriver(send_w3c_request=True)
 
+    # W3c capability flag is ignored in a legacy format request.
     driver = self.CreateDriver(send_w3c_capability=True)
     self.assertFalse(driver.w3c_compliant)
 
+    # W3C compliant responses should only be received when the capability has
+    # been set and the request was sent in the correct format.
     driver = self.CreateDriver(send_w3c_capability=True, send_w3c_request=True)
     self.assertTrue(driver.w3c_compliant)