Support converting utf-16 files when importing w3c tests

Previously, the test converter assumed that input files are always valid utf-8;
this change makes the converter also support utf-16 files. There are some files
in the wpt repo that are not valid utf-8 but are valid utf-16, e.g.
web-platform-tests/html/infrastructure/urls/resolving-urls/query-encoding/utf-16be.html.
BUG=463001

Review-Url: https://codereview.chromium.org/2037743002
Cr-Commit-Position: refs/heads/master@{#397775}

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

@@ -47,7 +47,10 @@ def convert_for_webkit(new_path, filename, reference_support_info, host=Host()):
     if filename.endswith('.css'):
         return converter.add_webkit_prefix_to_unprefixed_properties(contents.decode('utf-8'))
     else:
-        converter.feed(contents.decode('utf-8'))
+        try:
+            converter.feed(contents.decode('utf-8'))
+        except UnicodeDecodeError:
+            converter.feed(contents.decode('utf-16'))
         converter.close()
         return converter.output()
 

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

@@ -33,7 +33,9 @@ from webkitpy.common.host import Host
 from webkitpy.common.system.outputcapture import OutputCapture
 from webkitpy.common.webkit_finder import WebKitFinder
 from webkitpy.thirdparty.BeautifulSoup import BeautifulSoup
-from webkitpy.w3c.test_converter import _W3CTestConverter
+from webkitpy.w3c.test_converter import _W3CTestConverter, convert_for_webkit
+from webkitpy.common.system.systemhost_mock import MockSystemHost
+from webkitpy.common.system.filesystem_mock import MockFileSystem
 
 DUMMY_FILENAME = 'dummy.html'
 DUMMY_PATH = 'dummy/testharness/path'
@@ -310,3 +312,16 @@ CONTENT OF TEST
             index -= 1
 
         return (test_properties, html)
+
+    def test_convert_for_webkit_with_non_utf8(self):
+        files = {'/file': 'e\x87[P',
+                 '/mock-checkout/third_party/WebKit/Source/core/css/CSSProperties.in': '', }
+        host = MockSystemHost(filesystem=MockFileSystem(files=files))
+        convert_for_webkit('', '/file', '', host)
+
+    # This test passes if no Exception is raised
+    def test_convert_for_webkit_with_utf8(self):
+        files = {'/file': 'foo',
+                 '/mock-checkout/third_party/WebKit/Source/core/css/CSSProperties.in': '', }
+        host = MockSystemHost(filesystem=MockFileSystem(files=files))
+        convert_for_webkit('', '/file', '', host)