Revert of [ObjC ARC] Converts ios/web:web to ARC.

ios/web/web_state/ui/web_view_js_utils.mm

 // Copyright 2014 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/ui/web_view_js_utils.h"
 
 #include <CoreFoundation/CoreFoundation.h>
 #import <WebKit/WebKit.h>
 
 #include "base/logging.h"
 #include "base/mac/foundation_util.h"
+#import "base/mac/scoped_nsobject.h"
 #include "base/memory/ptr_util.h"
 #include "base/strings/sys_string_conversions.h"
 #include "base/values.h"
 
-#if !defined(__has_feature) || !__has_feature(objc_arc)
-#error "This file requires ARC support."
-#endif
-
 namespace {
 
 // Converts result of WKWebView script evaluation to base::Value, parsing
 // |wk_result| up to a depth of |max_depth|.
 std::unique_ptr<base::Value> ValueResultFromWKResult(id wk_result,
                                                      int max_depth) {
   if (!wk_result)
     return nullptr;
 
   std::unique_ptr<base::Value> result;
 
   if (max_depth < 0) {
     DLOG(WARNING) << "JS maximum recursion depth exceeded.";
     return result;
   }
 
-  CFTypeRef typeRef = (__bridge CFTypeRef)wk_result;
-  CFTypeID result_type = CFGetTypeID(typeRef);
+  CFTypeID result_type = CFGetTypeID(wk_result);
   if (result_type == CFStringGetTypeID()) {
     result.reset(new base::Value(base::SysNSStringToUTF16(wk_result)));
     DCHECK(result->IsType(base::Value::Type::STRING));
   } else if (result_type == CFNumberGetTypeID()) {
     result.reset(new base::Value([wk_result doubleValue]));
     DCHECK(result->IsType(base::Value::Type::DOUBLE));
   } else if (result_type == CFBooleanGetTypeID()) {
     result.reset(new base::Value(static_cast<bool>([wk_result boolValue])));
     DCHECK(result->IsType(base::Value::Type::BOOLEAN));
   } else if (result_type == CFNullGetTypeID()) {
@@ skipping 40 matching lines @@
 }
 
 void ExecuteJavaScript(WKWebView* web_view,
                        NSString* script,
                        JavaScriptResultBlock completion_handler) {
   DCHECK([script length]);
   if (!web_view && completion_handler) {
     dispatch_async(dispatch_get_main_queue(), ^{
       NSString* error_message =
           @"JS evaluation failed because there is no web view.";
-      NSError* error = [[NSError alloc]
+      base::scoped_nsobject<NSError> error([[NSError alloc]
           initWithDomain:kJSEvaluationErrorDomain
                     code:JS_EVALUATION_ERROR_CODE_NO_WEB_VIEW
-                userInfo:@{NSLocalizedDescriptionKey : error_message}];
+                userInfo:@{NSLocalizedDescriptionKey : error_message}]);
       completion_handler(nil, error);
     });
     return;
   }
 
   [web_view evaluateJavaScript:script completionHandler:completion_handler];
 }
 
 }  // namespace web