🤠 Mark testMediaCaptureNotificationVisibleAfterAdoption as flaky.

This test is flaky. In particular on the Marshmallow Tablet Tester:
https://ci.chromium.org/p/chromium/builders/ci/Marshmallow%20Tablet%20Tester/b8872140678652429312

TBR=adithyas@chromium.org

Bug: 1115888
Change-Id: I933c0e369d93aa343576f03c3f76af8c0ddbc82b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2352936Reviewed-by: Arthur Sonzogni <arthursonzogni@chromium.org>
Commit-Queue: Arthur Sonzogni <arthursonzogni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#797618}

chrome/android/javatests/src/org/chromium/chrome/browser/portals/PortalsTest.java

@@ -34,6 +34,7 @@ import org.chromium.base.test.util.CallbackHelper;
 import org.chromium.base.test.util.CommandLineFlags;
 import org.chromium.base.test.util.DisabledTest;
 import org.chromium.base.test.util.Feature;
+import org.chromium.base.test.util.FlakyTest;
 import org.chromium.base.test.util.MinAndroidSdkLevel;
 import org.chromium.chrome.R;
 import org.chromium.chrome.browser.ChromeActivity;
@@ -548,6 +549,7 @@ public class PortalsTest {
     @LargeTest
     @Feature({"Portals"})
     @MinAndroidSdkLevel(Build.VERSION_CODES.M)
+    @FlakyTest(message = "https://crbug.com/1115888")
     public void testMediaCaptureNotificationVisibleAfterAdoption() throws Exception {
         String mainUrl = mTestServer.getURL("/chrome/test/data/android/portals/media-capture.html");
         mActivityTestRule.startMainActivityWithURL(mainUrl);