[DevTools] Reduce API surface of String16.

third_party/WebKit/Source/platform/v8_inspector/RemoteObjectId.cpp

 // 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.
 
 #include "platform/v8_inspector/RemoteObjectId.h"
 
 #include "platform/inspector_protocol/Parser.h"
 #include "platform/inspector_protocol/Platform.h"
 #include "platform/inspector_protocol/Values.h"
 
@@ skipping 48 matching lines @@
     if (!success) {
         *errorString = "Invalid call frame id";
         return nullptr;
     }
 
     return result;
 }
 
 String16 RemoteCallFrameId::serialize(int injectedScriptId, int frameOrdinal)
 {
-    return "{\"ordinal\":" + String16::fromInteger(frameOrdinal) + ",\"injectedScriptId\":" + String16::fromInteger(injectedScriptId) + "}";
+    return "{\"ordinal\":" + protocol::string16FromInteger(frameOrdinal) + ",\"injectedScriptId\":" + protocol::string16FromInteger(injectedScriptId) + "}";
 }
 
 } // namespace blink