[ObjC ARC] Converts ios/chrome/browser/omaha:unit_tests to ARC.

ios/chrome/browser/omaha/omaha_service_unittest.mm

 // Copyright 2012 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.
 
 #import "ios/chrome/browser/omaha/omaha_service.h"
 
 #include <regex.h>
 #include <sys/types.h>
 
 #include "base/bind.h"
@@ skipping 10 matching lines @@
 #include "ios/chrome/test/ios_chrome_scoped_testing_chrome_browser_state_manager.h"
 #include "ios/public/provider/chrome/browser/chrome_browser_provider.h"
 #include "ios/public/provider/chrome/browser/omaha/omaha_service_provider.h"
 #include "ios/web/public/test/test_web_thread_bundle.h"
 #include "ios/web/public/web_thread.h"
 #include "net/url_request/test_url_fetcher_factory.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "testing/gtest_mac.h"
 #include "testing/platform_test.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace {
 
 const char kUserDataDir[] = FILE_PATH_LITERAL(".");
 
 }  // namespace
 
 class OmahaServiceTest : public PlatformTest {
  public:
   OmahaServiceTest()
       : need_update_(false),
@@ skipping 453 matching lines @@
       "\" status=\"ok\">"
       "<updatecheck status=\"noupdate\"/><ping status=\"ok\"/>"
       "</app></response>";
   fetcher->SetResponseString(response);
   fetcher->delegate()->OnURLFetchComplete(fetcher);
 
   EXPECT_FALSE(service.IsNextPingInstallRetry());
   id1 = service.GetNextPingRequestId(OmahaService::USAGE_PING);
   ASSERT_NE(id1, service.GetNextPingRequestId(OmahaService::USAGE_PING));
 }