[ChromeDriver] Add tests names where Chrome retried to start to logs

Change-Id: I6d2cf48b16562f60e35b2d499bfbbe25c12533c1
Reviewed-on: https://chromium-review.googlesource.com/c/1327168Reviewed-by: John Chen <johnchen@chromium.org>
Commit-Queue: Tatiana Buldina <buldina@chromium.org>
Cr-Commit-Position: refs/heads/master@{#606875}

chrome/test/chromedriver/client/chromedriver.py

@@ -124,6 +124,7 @@ class ChromeDriver(object):
   """Starts and controls a single Chrome instance on this machine."""
 
   retry_count = 0
+  retried_tests = []
 
   def __init__(self, *args, **kwargs):
     try:
@@ -134,6 +135,7 @@ class ChromeDriver(object):
       else:
         if ChromeDriver.retry_count < MAX_RETRY_COUNT:
           ChromeDriver.retry_count = ChromeDriver.retry_count + 1
+          ChromeDriver.retried_tests.append(kwargs.get('test_name'))
           self._InternalInit(*args, **kwargs)
         else:
           raise

chrome/test/chromedriver/test/run_py_tests.py

@@ -3037,7 +3037,9 @@ class ZChromeStartRetryCountTest(unittest.TestCase):
 
   def testChromeStartRetryCount(self):
     self.assertEquals(0, chromedriver.ChromeDriver.retry_count,
-                      "Chrome was retried to start during suite execution")
+                      "Chrome was retried to start during suite execution "
+                      "in following tests:\n" +
+                      ', \n'.join(chromedriver.ChromeDriver.retried_tests))
 
 if __name__ == '__main__':
   parser = optparse.OptionParser()