Change GitCL.trigger_try_jobs to accept any sequence.

GitCL.trigger_try_jobs is called with different types in test_importer.py and
rebaseline_cl.py. It's not very complicated to just make it accept any
sequence. This CL adds a bug fix and unit test.

Bug: 776585
Change-Id: Ie9d57e1d388ef08fb24d78b9a61392a70b76723b
Reviewed-on: https://chromium-review.googlesource.com/729541Reviewed-by: Joshua Bell <jsbell@chromium.org>
Commit-Queue: Quinten Yearsley <qyearsley@chromium.org>
Cr-Commit-Position: refs/heads/master@{#510275}

third_party/WebKit/Tools/Scripts/webkitpy/common/net/git_cl.py

@@ -55,7 +55,7 @@ class GitCL(object):
         # which are all on the master tryserver.blink, except android_blink_rel.
         if 'android_blink_rel' in builders:
             self.run(['try', '-b', 'android_blink_rel'])
-            builders = builders - {'android_blink_rel'}
+            builders = set(builders) - {'android_blink_rel'}
         # The master name has to be explicitly added for some builders since
         # git cl try doesn't necessarily have a reliable map of builder names
         # to masters. See https://crbug.com/700552.

third_party/WebKit/Tools/Scripts/webkitpy/common/net/git_cl_unittest.py

@@ -53,6 +53,24 @@ class GitCLTest(unittest.TestCase):
             ],
         ])
 
+    def test_trigger_try_jobs_with_list(self):
+        host = MockHost()
+        git_cl = GitCL(host, auth_refresh_token_json='token.json')
+        git_cl.trigger_try_jobs(['builder-a', 'android_blink_rel'])
+        self.assertEqual(host.executive.calls, [
+            [
+                'git', 'cl', 'try',
+                '-b', 'android_blink_rel',
+                '--auth-refresh-token-json', 'token.json'
+            ],
+            [
+                'git', 'cl', 'try',
+                '-m', 'tryserver.blink',
+                '-b', 'builder-a',
+                '--auth-refresh-token-json', 'token.json'
+            ],
+        ])
+
     def test_trigger_try_jobs_with_android_blink_rel(self):
         # The trigger_try_jobs method may be called with an immutable set.
         # It has special logic which assumes most builders to trigger are