Adds functionality to update-w3c-test-expectations

This cl adds functionality to the skip so that it skips adding
the failing test line if it already exists in TestExpectations.

BUG=625254

Review-Url: https://codereview.chromium.org/2174073002
Cr-Commit-Position: refs/heads/master@{#407349}

third_party/WebKit/Tools/Scripts/webkitpy/w3c/update_w3c_test_expectations.py

@@ -230,11 +230,12 @@ class W3CExpectationsLineAdder(object):
         to LayoutTest/TestExpectations. Checks the file for the string
         '# Tests added from W3C auto import bot' and writes expectation
         lines directly under it. If not found, it writes to the end of
-        the file.
+        the file. If the test name is already in LayoutTests/TestExpectations,
+        the line will be skipped.
 
         Args:
             host: A Host object.
-            path: The path to the file LayoutTest/TestExpectations.
+            path: The path to the file LayoutTests/TestExpectations.
             line_list: A list of w3c test expectations lines.
 
         Returns:
@@ -245,6 +246,10 @@ class W3CExpectationsLineAdder(object):
         w3c_comment_line_index = file_contents.find(comment_line)
         all_lines = ''
         for line in line_list:
+            end_bracket_index = line.split().index(']')
+            test_name = line.split()[end_bracket_index + 1]
+            if test_name in file_contents:
+                continue
             all_lines += str(line) + '\n'
         all_lines = all_lines[:-1]
         if w3c_comment_line_index == -1:

third_party/WebKit/Tools/Scripts/webkitpy/w3c/update_w3c_test_expectations_unittest.py

@@ -90,18 +90,28 @@ class UpdateW3CTestExpectationsTest(unittest.TestCase, W3CExpectationsLineAdder)
         host = MockHost()
         line_adder = W3CExpectationsLineAdder(host)
         line_adder._host.filesystem.files = {'TestExpectations': '# Tests added from W3C auto import bot\n'}
-        line_list = ['fake crbug [foo] fake/file/path.html [Pass]']
+        line_list = ['fake crbug [ foo ] fake/file/path.html [Pass]']
         path = 'TestExpectations'
         line_adder.write_to_test_expectations(line_adder, path, line_list)
         value = line_adder._host.filesystem.read_text_file(path)
-        self.assertEqual(value, '# Tests added from W3C auto import bot\nfake crbug [foo] fake/file/path.html [Pass]\n')
+        self.assertEqual(value, '# Tests added from W3C auto import bot\nfake crbug [ foo ] fake/file/path.html [Pass]\n')
 
     def test_write_to_test_expectations_to_eof(self):
         host = MockHost()
         line_adder = W3CExpectationsLineAdder(host)
         line_adder._host.filesystem.files['TestExpectations'] = 'not empty\n'
-        line_list = ['fake crbug [foo] fake/file/path.html [Pass]']
+        line_list = ['fake crbug [ foo ] fake/file/path.html [Pass]']
         path = 'TestExpectations'
         line_adder.write_to_test_expectations(line_adder, path, line_list)
         value = line_adder.filesystem.read_text_file(path)
-        self.assertEqual(value, 'not empty\n\n# Tests added from W3C auto import bot\nfake crbug [foo] fake/file/path.html [Pass]')
+        self.assertEqual(value, 'not empty\n\n# Tests added from W3C auto import bot\nfake crbug [ foo ] fake/file/path.html [Pass]')
+
+    def test_write_to_test_expectations_skip_lines(self):
+        host = MockHost()
+        line_adder = W3CExpectationsLineAdder(host)
+        line_adder._host.filesystem.files['TestExpectations'] = 'dont copy me\n'
+        line_list = ['[ ] dont copy me', '[ ] but copy me']
+        path = 'TestExpectations'
+        line_adder.write_to_test_expectations(line_adder, path, line_list)
+        value = line_adder.filesystem.read_text_file(path)
+        self.assertEqual(value, 'dont copy me\n\n# Tests added from W3C auto import bot\n[ ] but copy me')