Disable flaky BackgroundFetchBrowserTest.OfflineItemCollection_SingleFileMetadata.

BUG=822944
TBR=peter@chromium.org

Change-Id: Ibf81ac125ecd066e6c90e1c21788f3938d8380fc
Reviewed-on: https://chromium-review.googlesource.com/967378Reviewed-by: Karan Bhatia <karandeepb@chromium.org>
Commit-Queue: Karan Bhatia <karandeepb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#543867}

chrome/browser/background_fetch/background_fetch_browsertest.cc

@@ -293,8 +293,9 @@ IN_PROC_BROWSER_TEST_F(BackgroundFetchBrowserTest,
   EXPECT_FALSE(guid.empty());
 }
 
+// TODO(crbug.com/822944): Disabled since flaky.
 IN_PROC_BROWSER_TEST_F(BackgroundFetchBrowserTest,
-                       OfflineItemCollection_SingleFileMetadata) {
+                       DISABLED_OfflineItemCollection_SingleFileMetadata) {
   // Starts a Background Fetch for a single to-be-downloaded file and waits for
   // the fetch to be registered with the offline items collection. We then
   // verify that all the appropriate values have been set.