Use explicit WebString conversions in extensions/

extensions/renderer/api/automation/automation_api_helper.cc

 // 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.
 
 #include "extensions/renderer/api/automation/automation_api_helper.h"
 
 #include "content/public/renderer/render_view.h"
 #include "extensions/common/extension_messages.h"
 #include "third_party/WebKit/public/web/WebAXObject.h"
 #include "third_party/WebKit/public/web/WebDocument.h"
@@ skipping 56 matching lines @@
           routing_id(), request_id, error, 0));
       return;
     }
 
     start_node = start_acc_obj.node();
     while (start_node.isNull()) {
       start_acc_obj = start_acc_obj.parentObject();
       start_node = start_acc_obj.node();
     }
   }
-  blink::WebString web_selector(selector);
+  blink::WebString web_selector = blink::WebString::fromUTF16(selector);
   blink::WebElement result_element = start_node.querySelector(web_selector);
   int result_acc_obj_id = 0;
   if (!result_element.isNull()) {
     blink::WebAXObject result_acc_obj = result_element.accessibilityObject();
     if (!result_acc_obj.isDetached()) {
       while (result_acc_obj.accessibilityIsIgnored())
         result_acc_obj = result_acc_obj.parentObject();
 
       result_acc_obj_id = result_acc_obj.axID();
     }
   }
   Send(new ExtensionHostMsg_AutomationQuerySelector_Result(
       routing_id(), request_id, error, result_acc_obj_id));
 }
 
 }  // namespace extensions