Fixes for re-enabling more MSVC level 4 warnings: mojo/ edition

mojo/services/public/cpp/view_manager/lib/view.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/public/cpp/view_manager/view.h"
 
 #include "mojo/services/public/cpp/view_manager/lib/view_manager_client_impl.h"
 #include "mojo/services/public/cpp/view_manager/lib/view_private.h"
 #include "mojo/services/public/cpp/view_manager/node.h"
 #include "mojo/services/public/cpp/view_manager/view_observer.h"
@@ skipping 57 matching lines @@
   canvas.DrawColor(color);
   SetContents(skia::GetTopDevice(*canvas.sk_canvas())->accessBitmap(true));
 }
 
 View::View(ViewManager* manager)
     : id_(static_cast<ViewManagerClientImpl*>(manager)->CreateView()),
       node_(NULL),
       manager_(manager) {}
 
 View::View()
-    : id_(-1),
+    : id_(static_cast<Id>(-1)),
       node_(NULL),
       manager_(NULL) {}
 
 View::~View() {
   ScopedDestructionNotifier notifier(this);
   // TODO(beng): It'd be better to do this via a destruction observer in the
   //             ViewManagerClientImpl.
   if (manager_)
     static_cast<ViewManagerClientImpl*>(manager_)->RemoveView(id_);
 }
 
 void View::LocalDestroy() {
   delete this;
 }
 
 }  // namespace view_manager
 }  // namespace mojo