android: Mark flaky tests with @RetryOnFailure

chrome/android/javatests/src/org/chromium/chrome/browser/download/DownloadActivityTest.java

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.chrome.browser.download;
 
 import android.content.Intent;
 import android.os.Handler;
 import android.os.Looper;
 import android.support.v7.widget.RecyclerView;
@@ skipping 234 matching lines @@
         mStubbedProvider.getDownloadDelegate().removeDownloadCallback.waitForCallback(0);
         assertEquals(1,
                 mStubbedProvider.getDownloadDelegate().checkExternalCallback.getCallCount());
         mStubbedProvider.getOfflinePageBridge().deleteItemCallback.waitForCallback(0);
         assertFalse(mStubbedProvider.getSelectionDelegate().isSelectionEnabled());
         assertEquals(8, mAdapter.getItemCount());
         assertEquals("0.00 GB used", mSpaceUsedDisplay.getText());
     }
 
     @MediumTest
+    @RetryOnFailure
     public void testUndoDelete() throws Exception {
         // Adapter positions:
         // 0 = date
         // 1 = download item #7
         // 2 = download item #8
         // 3 = date
         // 4 = download item #6
         // 5 = offline page #3
 
         SnackbarManager.setDurationForTesting(5000);
@@ skipping 58 matching lines @@
         assertEquals(0,
                 mStubbedProvider.getDownloadDelegate().removeDownloadCallback.getCallCount());
         assertEquals(0,
                 mStubbedProvider.getOfflinePageBridge().deleteItemCallback.getCallCount());
         assertFalse(mStubbedProvider.getSelectionDelegate().isSelectionEnabled());
         assertEquals(14, mAdapter.getItemCount());
         assertEquals("7.00 GB used", mSpaceUsedDisplay.getText());
     }
 
     @MediumTest
+    @RetryOnFailure
     public void testUndoDeleteDuplicatesSelected() throws Exception {
         // Adapter positions:
         // 0 = date
         // 1 = download item #7
         // 2 = download item #8
         // ....
 
         SnackbarManager.setDurationForTesting(5000);
 
         // Add duplicate items.
@@ skipping 227 matching lines @@
 
         ThreadUtils.runOnUiThread(new Runnable() {
             @Override
             public void run() {
                 itemView.performLongClick();
             }
         });
         mAdapterObserver.onSelectionCallback.waitForCallback(callCount, 1);
     }
 }