Change TypeConverter<X,Y>::ConvertFrom and ConvertTo into a single symmetric

mojo/services/native_viewport/native_viewport_impl.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 "mojo/services/native_viewport/native_viewport_impl.h"
 
 #include "base/bind.h"
 #include "base/macros.h"
 #include "base/message_loop/message_loop.h"
 #include "base/time/time.h"
@@ skipping 100 matching lines @@
       platform_viewport_->ReleaseCapture();
       break;
     default:
       break;
   }
 
   if (waiting_for_event_ack_ && IsRateLimitedEventType(ui_event))
     return false;
 
   client()->OnEvent(
-      TypeConverter<EventPtr, ui::Event>::ConvertFrom(*ui_event),
-      base::Bind(&NativeViewportImpl::AckEvent,
-                 weak_factory_.GetWeakPtr()));
+      Event::From(*ui_event),
+      base::Bind(&NativeViewportImpl::AckEvent, weak_factory_.GetWeakPtr()));
   waiting_for_event_ack_ = true;
   return false;
 }
 
 void NativeViewportImpl::OnDestroyed() {
   client()->OnDestroyed();
 }
 
 void NativeViewportImpl::AckEvent() {
   waiting_for_event_ack_ = false;
 }
 
 }  // namespace mojo