Split ExtensionSystem interface from ExtensionSystemImpl implementation, part 1.

chrome/browser/extensions/api/serial/serial_api.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 "chrome/browser/extensions/api/serial/serial_api.h"
 
 #include <algorithm>
 
 #include "base/values.h"
-#include "chrome/browser/extensions/extension_system.h"
 #include "chrome/browser/extensions/api/serial/serial_connection.h"
 #include "chrome/browser/extensions/api/serial/serial_event_dispatcher.h"
 #include "chrome/browser/extensions/api/serial/serial_port_enumerator.h"
 #include "chrome/common/extensions/api/serial.h"
 #include "content/public/browser/browser_thread.h"
+#include "extensions/browser/extension_system.h"
 
 using content::BrowserThread;
 
 namespace extensions {
 
 namespace api {
 
 namespace {
 
 // It's a fool's errand to come up with a default bitrate, because we don't get
@@ skipping 382 matching lines @@
     return;
   }
 
   bool success = connection->SetControlSignals(params_->signals);
   results_ = serial::SetControlSignals::Results::Create(success);
 }
 
 }  // namespace api
 
 }  // namespace extensions