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

ios/web/web_state/js/page_script_util_unittest.mm

 // Copyright 2015 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/web_state/js/page_script_util.h"
 
 #import <UIKit/UIKit.h>
 #import <WebKit/WebKit.h>
 
-#import "base/mac/scoped_nsobject.h"
 #include "base/strings/sys_string_conversions.h"
 #import "base/test/ios/wait_util.h"
 #include "ios/web/public/test/fakes/test_browser_state.h"
 #import "ios/web/public/test/fakes/test_web_client.h"
 #import "ios/web/public/test/js_test_util.h"
 #include "ios/web/public/test/web_test.h"
 #import "ios/web/public/web_view_creation_util.h"
 #import "testing/gtest_mac.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace web {
 namespace {
 
 // A test fixture for testing the page_script_util methods.
 typedef WebTest PageScriptUtilTest;
 
 // Tests that WKWebView early page script is a valid script that injects global
 // __gCrWeb object.
 TEST_F(PageScriptUtilTest, WKWebViewEarlyPageScript) {
   WKWebView* web_view = BuildWKWebView(CGRectZero, GetBrowserState());
   ExecuteJavaScript(web_view, GetEarlyPageScript(GetBrowserState()));
   EXPECT_NSEQ(@"object", ExecuteJavaScript(web_view, @"typeof __gCrWeb"));
 }
 
 // Tests that embedder's WKWebView script is included into early script.
 TEST_F(PageScriptUtilTest, WKEmbedderScript) {
   GetWebClient()->SetEarlyPageScript(@"__gCrEmbedder = {};");
   WKWebView* web_view = BuildWKWebView(CGRectZero, GetBrowserState());
   ExecuteJavaScript(web_view, GetEarlyPageScript(GetBrowserState()));
   EXPECT_NSEQ(@"object", ExecuteJavaScript(web_view, @"typeof __gCrEmbedder"));
 }
 
 }  // namespace
 }  // namespace web