Disable FileManagerFileWatcherTest.WatchLocalFile in unit_tests.

It is flaky. Disabling it for now.

not run anything.

Bug: 813483
Test: unit_tests --grest_filter=FileManagerFileWatcherTest.WatchLocalFile did
Change-Id: I826f3f4ca942c939916207bca97569661d92351d
Reviewed-on: https://chromium-review.googlesource.com/923616Reviewed-by: Yoshiki Iguchi <yoshiki@chromium.org>
Commit-Queue: Naoki Fukino <fukino@chromium.org>
Cr-Commit-Position: refs/heads/master@{#537602}

chrome/browser/chromeos/file_manager/file_watcher_unittest.cc

@@ -107,7 +107,8 @@ TEST_F(FileManagerFileWatcherTest, AddSameExtensionMultipleTimes) {
   ASSERT_EQ(0U, extension_ids.size());
 }
 
-TEST_F(FileManagerFileWatcherTest, WatchLocalFile) {
+// Disabled for flakiness. crbug.com/813483.
+TEST_F(FileManagerFileWatcherTest, DISABLED_WatchLocalFile) {
   const base::FilePath kVirtualPath =
       base::FilePath::FromUTF8Unsafe("foo/bar.txt");
   const char kExtensionId[] = "extension-id";