Adds support for running unittests using XCTest on iOS.

base/test/test_suite.cc

 // Copyright (c) 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.
 
 #include "base/test/test_suite.h"
 
 #include <memory>
 
 #include "base/at_exit.h"
 #include "base/base_paths.h"
@@ skipping 220 matching lines @@
 #endif
 
   Initialize();
   std::string client_func =
       CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
           switches::kTestChildProcess);
 
   // Check to see if we are being run as a client process.
   if (!client_func.empty())
     return multi_process_function_list::InvokeChildProcessTest(client_func);
+
 #if defined(OS_IOS)
+  if (IsRunningWithXCTest()) {
+    // XCTest will drive the tests if running in XCTest mode on iOS.  There is
+    // no need to run the tests here or to tear down the test suite.
+    return 0;
+  }
   test_listener_ios::RegisterTestEndListener();
 #endif
 
   int result = RUN_ALL_TESTS();
 
 #if defined(OS_MACOSX)
   // This MUST happen before Shutdown() since Shutdown() tears down
   // objects (such as NotificationService::current()) that Cocoa
   // objects use to remove themselves as observers.
   scoped_pool.Recycle();
@@ skipping 131 matching lines @@
 
 void TestSuite::Shutdown() {
   base::debug::StopProfiling();
 
   // Clear the FeatureList that was created by Initialize().
   if (created_feature_list_)
     FeatureList::ClearInstanceForTesting();
 }
 
 }  // namespace base