Use explicit WebString conversions in remaining content files

content/renderer/devtools/devtools_agent.cc

 // Copyright (c) 2012 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 "content/renderer/devtools/devtools_agent.h"
 
 #include <stddef.h>
 
 #include <map>
 
@@ skipping 312 matching lines @@
     error_value->SetString("message", error.message);
     error_value->SetBoolean("critical", error.critical);
     error_value->SetInteger("line", error.line);
     error_value->SetInteger("column", error.column);
     if (error.critical)
       failed = true;
     errors->Append(std::move(error_value));
   }
 
   WebString url = frame_->GetWebFrame()->document().manifestURL().string();
-  result->SetString("url", url);
+  result->SetString("url", url.utf16());
   if (!failed)
     result->SetString("data", debug_info.raw_data);
   result->Set("errors", errors.release());
   response->Set("result", result.release());
 
   std::string json_message;
   base::JSONWriter::Write(*response, &json_message);
   SendChunkedProtocolMessage(this, routing_id(), session_id, call_id,
                              json_message, std::string());
 }
 
 }  // namespace content