Disable offline pages tests on iOS

components/offline_pages/core/background/request_coordinator_unittest.cc

 // 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.
 
 #include "components/offline_pages/core/background/request_coordinator.h"
 
 #include <memory>
 #include <string>
 #include <utility>
 #include <vector>
@@ skipping 1283 matching lines @@
   // Wait for async get to finish.
   WaitForCallback();
   PumpLoop();
 
   // Check that the statuses found in the callback match what we expect.
   EXPECT_EQ(2UL, last_requests().size());
   EXPECT_EQ(kRequestId1, last_requests().at(0)->request_id());
   EXPECT_EQ(kRequestId2, last_requests().at(1)->request_id());
 }
 
-#if defined(OS_IOS)
-// Flaky on IOS. http://crbug/663311
-#define MAYBE_PauseAndResumeObserver DISABLED_PauseAndResumeObserver
-#else
-#define MAYBE_PauseAndResumeObserver PauseAndResumeObserver
-#endif
-TEST_F(RequestCoordinatorTest, MAYBE_PauseAndResumeObserver) {
+TEST_F(RequestCoordinatorTest, PauseAndResumeObserver) {
   // Set low-end device status to actual status.
   SetIsLowEndDeviceForTest(base::SysInfo::IsLowEndDevice());
 
   // Add a request to the queue.
   AddRequest1();
   PumpLoop();
 
   // Pause the request.
   std::vector<int64_t> request_ids;
   request_ids.push_back(kRequestId1);
@@ skipping 258 matching lines @@
   PumpLoop();
 
   // The last time would trigger the snapshot on last retry and succeed.
   EXPECT_FALSE(OfflinerWasCanceled());
   EXPECT_EQ(RequestCoordinator::BackgroundSavePageResult::SUCCESS,
             observer().last_status());
   EXPECT_TRUE(observer().completed_called());
 }
 
 }  // namespace offline_pages