[ObjC ARC] Converts ios/web/public/test:test to ARC.

ios/web/public/test/web_view_interaction_test_util.mm

 // 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.
 
 #import "ios/web/public/test/web_view_interaction_test_util.h"
 
 #import "base/mac/bind_objc_block.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #import "base/test/ios/wait_util.h"
 #import "ios/testing/wait_util.h"
 #import "ios/web/public/web_state/ui/crw_web_view_scroll_view_proxy.h"
 #import "ios/web/web_state/ui/crw_web_controller.h"
 #import "ios/web/web_state/ui/crw_web_view_proxy_impl.h"
 #import "ios/web/web_state/web_state_impl.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 using web::NavigationManager;
 
 namespace web {
 namespace test {
 
 enum ElementAction {
   ELEMENT_ACTION_CLICK,
   ELEMENT_ACTION_FOCUS,
   ELEMENT_ACTION_SUBMIT
 };
 
 std::unique_ptr<base::Value> ExecuteJavaScript(web::WebState* web_state,
                                                const std::string& script) {
   __block std::unique_ptr<base::Value> result;
   __block bool did_finish = false;
   web_state->ExecuteJavaScript(base::UTF8ToUTF16(script),
-                               base::BindBlock(^(const base::Value* value) {
+                               base::BindBlockArc(^(const base::Value* value) {
                                  if (value)
                                    result = value->CreateDeepCopy();
                                  did_finish = true;
                                }));
 
   bool completed = testing::WaitUntilConditionOrTimeout(
       testing::kWaitForJSCompletionTimeout, ^{
         return did_finish;
       });
   if (!completed) {
@@ skipping 128 matching lines @@
 }
 
 bool SubmitWebViewFormWithId(web::WebState* web_state,
                              const std::string& form_id) {
   return RunActionOnWebViewElementWithId(web_state, form_id,
                                          ELEMENT_ACTION_SUBMIT);
 }
 
 }  // namespace test
 }  // namespace web