Use GetSwitchValueASCII.

chrome/test/unit/chrome_test_suite.h

Index: chrome/test/unit/chrome_test_suite.h
diff --git a/chrome/test/unit/chrome_test_suite.h b/chrome/test/unit/chrome_test_suite.h
index 178b62ac752c2c9941567bf94c9fc9d0b64cf7ca..bd05e0d71eb3179d01102df398f78394f78fd22c 100644
--- a/chrome/test/unit/chrome_test_suite.h
+++ b/chrome/test/unit/chrome_test_suite.h
@@ -86,9 +86,9 @@ class ChromeTestSuite : public TestSuite {
     // user data directory that lives alongside the current app.
     // NOTE: The user data directory will be erased before each UI test that
     //       uses it, in order to ensure consistency.
-    FilePath user_data_dir = FilePath::FromWStringHack(
-        CommandLine::ForCurrentProcess()->GetSwitchValue(
-            switches::kUserDataDir));
+    FilePath user_data_dir =
+        CommandLine::ForCurrentProcess()->GetSwitchValuePath(
+            switches::kUserDataDir);
     if (user_data_dir.empty() &&
         file_util::CreateNewTempDirectory(FILE_PATH_LITERAL("chrome_test_"),
                                           &user_data_dir)) {