Move SystemLogsSource class into new file

chrome/browser/chromeos/system_logs/dbus_log_source.h

 // 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.
 
 #ifndef CHROME_BROWSER_CHROMEOS_SYSTEM_LOGS_DBUS_LOG_SOURCE_H_
 #define CHROME_BROWSER_CHROMEOS_SYSTEM_LOGS_DBUS_LOG_SOURCE_H_
 
 #include "base/macros.h"
-#include "chrome/browser/feedback/system_logs/system_logs_fetcher.h"
+#include "chrome/browser/feedback/system_logs/system_logs_source.h"
 
 namespace system_logs {
 
 // Fetches memory usage details.
 class DBusLogSource : public SystemLogsSource {
  public:
   DBusLogSource();
   ~DBusLogSource() override;
 
   // SystemLogsSource override.
   void Fetch(const SysLogsSourceCallback& request) override;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(DBusLogSource);
 };
 
 }  // namespace system_logs
 
 #endif  // CHROME_BROWSER_CHROMEOS_SYSTEM_LOGS_DBUS_LOG_SOURCE_H_