[ObjC ARC] Converts ios/web:ios_web_web_state_js_unittests to ARC.

ios/web/web_state/js/crw_js_injection_manager_unittest.mm

 // Copyright 2013 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/web/public/web_state/js/crw_js_injection_manager.h"
 
 #include <stddef.h>
 #import <Foundation/Foundation.h>
 
 #import "ios/web/public/test/web_test_with_web_state.h"
 #import "ios/web/public/web_state/js/crw_js_injection_receiver.h"
 #import "ios/web/public/web_state/web_state.h"
 #import "testing/gtest_mac.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 // Testing class of JsInjectioManager that has no dependencies.
 @interface TestingCRWJSBaseManager : CRWJSInjectionManager
 @end
 
 @implementation TestingCRWJSBaseManager
 
 - (NSString*)staticInjectionContent {
   return @"base = {};";
 }
 
@@ skipping 142 matching lines @@
   EXPECT_NSNE([manager injectionContent], [manager injectionContent]);
 }
 
 // Tests that checking for an uninjected presence beacon returns false.
 TEST_F(JsInjectionManagerTest, WebControllerCheckForUninjectedScript) {
   EXPECT_FALSE([web_state()->GetJSInjectionReceiver()
       scriptHasBeenInjectedForClass:Nil]);
 }
 
 }  // namespace web