[ChromeDriver] Extract sessionId from W3C response

In W3C mode for ChromeDriver, the response format changed. Code
was modified to extract sessionId from the new response format.

Bug: chromedriver:3076
Change-Id: Iaf749fa480fcbe541d8b520357c4344c79241dc0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1746787Reviewed-by: John Chen <johnchen@chromium.org>
Commit-Queue: Tricia Crichton <triciac@chromium.org>
Cr-Commit-Position: refs/heads/master@{#686452}

chrome/test/chromedriver/log_replay/client_replay.py

@@ -748,8 +748,13 @@ class CommandSequence(object):
           self._id_map[id_old] = id_new
         self._staged_logged_ids = None
 
-    if "sessionId" in response and self._staged_logged_session_id:
-      self._id_map[self._staged_logged_session_id] = response["sessionId"]
+    # In W3C format, the http response is a single key dict,
+    # where the value is another dictionary
+    # sessionId is contained in the nested dictionary
+    if ("value" in response and "sessionId" in response["value"]
+        and self._staged_logged_session_id):
+      self._id_map[self._staged_logged_session_id] = (
+        response["value"]["sessionId"])
       self._staged_logged_session_id = None
 
   def _IngestLoggedResponse(self, response):

chrome/test/chromedriver/log_replay/client_replay_unittest.py

@@ -116,6 +116,23 @@ class ChromeDriverClientReplayUnitTest(unittest.TestCase):
     self.assertEqual(response.GetPayloadPrimitive(), {"param2": 42})
     self.assertEqual(response.session_id, _SESSION_ID)
 
+  def testIngestRealResponseInitSession(self):
+    real_resp = {u'value': {
+        u'sessionId': u'b15232d5497ec0d8300a5a1ea56f33ce',
+        u'capabilities': {
+            u'browserVersion': u'76.0.3809.100',
+            u'browserName': u'chrome',
+        }
+    }}
+
+    command_sequence = client_replay.CommandSequence()
+    command_sequence._staged_logged_session_id = _SESSION_ID_ALT
+    command_sequence._IngestRealResponse(real_resp)
+
+    self.assertEqual(
+        command_sequence._id_map[_SESSION_ID_ALT], _SESSION_ID)
+    self.assertEqual(command_sequence._staged_logged_session_id, None)
+
   def testGetPayload_simple(self):
     string_buffer = StringIO.StringIO(_RESPONSE_ONLY)
     header = string_buffer.readline()