Add support for Mimo connected to CfM running in meeting mode.

BUG=None
TEST=Tested on local setup.

Change-Id: I3b51f0ce0931259c66a480785108d6b20e21a795
Reviewed-on: https://chromium-review.googlesource.com/506510
Reviewed-by: Harpreet Grewal <harpreet@chromium.org>
Reviewed-by: Min Zhuo <mzhuo@chromium.org>
Commit-Queue: Min Zhuo <mzhuo@chromium.org>
Tested-by: Min Zhuo <mzhuo@chromium.org>
diff --git a/client/cros/multimedia/cfm_facade_native.py b/client/cros/multimedia/cfm_facade_native.py
index 6466ea7..f209644 100644
--- a/client/cros/multimedia/cfm_facade_native.py
+++ b/client/cros/multimedia/cfm_facade_native.py
@@ -66,10 +66,17 @@
                 self._resource._browser, self._EXT_ID)
         ext_urls = set([context.EvaluateJavaScript('location.href;')
                         for context in ext_contexts])
-        expected_urls = set(
+        if len(ext_urls) == 2:
+            expected_urls = set(
                 ['chrome-extension://' + self._EXT_ID + '/' + path
                  for path in ['hangoutswindow.html?windowid=0',
                               '_generated_background_page.html']])
+        if len(ext_urls) == 3:
+            expected_urls = set(
+                ['chrome-extension://' + self._EXT_ID + '/' + path
+                 for path in ['hangoutswindow.html?windowid=0',
+                              'hangoutswindow.html?windowid=1',
+                              '_generated_background_page.html']])
         if expected_urls != ext_urls:
             raise error.TestFail(
                     'Unexpected extension context urls, expected %s, got %s'