Disable RemoveListenerAndModifyGallery on win and linux

The test has been very flaky recently:
https://test-results.appspot.com/dashboards/flakiness_dashboard.html#testType=browser_tests%20(with%20patch)&tests=MediaGalleriesGalleryWatchApiTest.RemoveListenerAndModifyGallery

TBR=dbertoni@chromium.org
Bug: 1150017

Change-Id: Ie5167d6db5477348b22d36d3e6198a7a3863b6db
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2557916Reviewed-by: Yi Gu <yigu@chromium.org>
Commit-Queue: Yi Gu <yigu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#830587}

chrome/browser/apps/platform_apps/api/media_galleries/media_galleries_watch_apitest.cc

@@ -220,8 +220,15 @@ IN_PROC_BROWSER_TEST_F(MediaGalleriesGalleryWatchApiTest,
   EXPECT_TRUE(got_correct_details.WaitUntilSatisfied());
 }
 
+// Test is flaky on windows and linux: crbug.com/1150017.
+#if defined(OS_WIN) || defined(OS_LINUX)
+#define MAYBE_RemoveListenerAndModifyGallery \
+  DISABLED_RemoveListenerAndModifyGallery
+#else
+#define MAYBE_RemoveListenerAndModifyGallery RemoveListenerAndModifyGallery
+#endif
 IN_PROC_BROWSER_TEST_F(MediaGalleriesGalleryWatchApiTest,
-                       RemoveListenerAndModifyGallery) {
+                       MAYBE_RemoveListenerAndModifyGallery) {
   if (!GalleryWatchesSupported())
     return;