git-cl: respect http.cookieFile for finding gitcookies

This allows people to configure their gitcookies file to be
whereever they want. As long as it actually exists and has
credentials in it, we'll accept it, just like git itself.

Change-Id: I4aa4806ddca0e61b28b003b0d3bc486407c13ab4
Reviewed-on: https://chromium-review.googlesource.com/951917Reviewed-by: Robbie Iannucci <iannucci@chromium.org>
Commit-Queue: Aaron Gable <agable@chromium.org>

gerrit_util.py

@@ -27,6 +27,7 @@ import urlparse
 from cStringIO import StringIO
 
 import gclient_utils
+import subprocess2
 from third_party import httplib2
 
 LOGGER = logging.getLogger()
@@ -166,6 +167,10 @@ class CookiesAuthenticator(Authenticator):
   def get_gitcookies_path(cls):
     if os.getenv('GIT_COOKIES_PATH'):
       return os.getenv('GIT_COOKIES_PATH')
+    try:
+      return subprocess2.check_output(
+          ['git', 'config', '--path', 'http.cookiefile']).strip()
+    except subprocess2.CalledProcessError:
       return os.path.join(os.environ['HOME'], '.gitcookies')
 
   @classmethod

tests/git_cl_test.py

@@ -3455,6 +3455,7 @@ class TestGitCl(TestCase):
     self.mock(git_cl._GitCookiesChecker, 'get_hosts_with_creds',
               lambda _, include_netrc=False: [])
     self.calls = [
+      ((['git', 'config', '--path', 'http.cookiefile'],), CERR1),
       ((['git', 'config', '--global', 'http.cookiefile'],), CERR1),
       (('os.path.exists', '~/.netrc'), True),
       (('ask_for_data', 'Press Enter to setup .gitcookies, '
@@ -3475,6 +3476,7 @@ class TestGitCl(TestCase):
     self.mock(git_cl._GitCookiesChecker, 'get_hosts_with_creds',
               lambda _, include_netrc=False: [])
     self.calls = [
+      ((['git', 'config', '--path', 'http.cookiefile'],), CERR1),
       ((['git', 'config', '--global', 'http.cookiefile'],),
        '/custom/.gitcookies'),
       (('os.path.exists', '/custom/.gitcookies'), False),