In run_webkit_tests, use host.environ to access gtest shard env vars.

third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/run_webkit_tests_unittest.py

Index: third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/run_webkit_tests_unittest.py
diff --git a/third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/run_webkit_tests_unittest.py b/third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/run_webkit_tests_unittest.py
index af355a927ef4d2082f054825c433ea5fbdbc557f..7265f9dd3ef9f6d5082c847aa50413c6282c2c02 100644
--- a/third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/run_webkit_tests_unittest.py
+++ b/third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/run_webkit_tests_unittest.py
@@ -245,16 +245,8 @@ class RunTest(unittest.TestCase, StreamTestingMixin):
         # Tests for the default of using one locked shard even in the case of more than one child process.
         if not self.should_test_processes:
             return
-        save_env_webkit_test_max_locked_shards = None
-        if "WEBKIT_TEST_MAX_LOCKED_SHARDS" in os.environ:
-            save_env_webkit_test_max_locked_shards = os.environ["WEBKIT_TEST_MAX_LOCKED_SHARDS"]
-            del os.environ["WEBKIT_TEST_MAX_LOCKED_SHARDS"]
         _, regular_output, _ = logging_run(['--debug-rwt-logging', '--child-processes', '2'], shared_port=False)
-        try:
-            self.assertTrue(any(['1 locked' in line for line in regular_output.buflist]))
-        finally:
-            if save_env_webkit_test_max_locked_shards:
-                os.environ["WEBKIT_TEST_MAX_LOCKED_SHARDS"] = save_env_webkit_test_max_locked_shards

[jeffcarp, 2016/10/03 17:27:48]

Is the above no longer necessary?

[qyearsley, 2016/10/03 18:29:51]

Nope, I believe not -- since by default, the environ of MockHost is empty or
nearly empty and so doesn't include WEBKIT_TEST_MAX_LOCKED_SHARDS, and the
purpose of this test method is to test the default behavior if that environment
variable is not set.

Saving, deleting and resetting the environment variable was necessary to make
the test non-flaky before because the test used the real set of environment
variables.

+        self.assertTrue(any('1 locked' in line for line in regular_output.buflist))
 
     def test_child_processes_2(self):
         if self.should_test_processes:
@@ -518,19 +510,16 @@ class RunTest(unittest.TestCase, StreamTestingMixin):
         tests_to_run = ['passes/error.html', 'passes/image.html', 'passes/platform_image.html', 'passes/text.html']
         host = MockHost()
 
-        os.environ['GTEST_SHARD_INDEX'] = '0'
-        os.environ['GTEST_TOTAL_SHARDS'] = '1'
+        host.environ['GTEST_SHARD_INDEX'] = '0'
+        host.environ['GTEST_TOTAL_SHARDS'] = '1'
         shard_0_tests_run = get_tests_run(tests_to_run, host=host)
         self.assertEqual(shard_0_tests_run, ['passes/error.html', 'passes/image.html'])
 
-        os.environ['GTEST_SHARD_INDEX'] = '1'
-        os.environ['GTEST_TOTAL_SHARDS'] = '1'
+        host.environ['GTEST_SHARD_INDEX'] = '1'
+        host.environ['GTEST_TOTAL_SHARDS'] = '1'
         shard_1_tests_run = get_tests_run(tests_to_run, host=host)
         self.assertEqual(shard_1_tests_run, ['passes/platform_image.html', 'passes/text.html'])
 
-        del os.environ['GTEST_SHARD_INDEX']
-        del os.environ['GTEST_TOTAL_SHARDS']
-
     def test_smoke_test(self):
         host = MockHost()
         smoke_test_filename = test.LAYOUT_TEST_DIR + '/SmokeTests'