Move UsbService to its own component.

chrome/browser/usb/usb_service.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_USB_USB_SERVICE_H_
-#define CHROME_BROWSER_USB_USB_SERVICE_H_
-
-#include <map>
-#include <utility>
-#include <vector>
-
-#include "base/basictypes.h"
-#include "base/memory/ref_counted.h"
-#include "base/memory/scoped_ptr.h"
-#include "base/message_loop/message_loop.h"
-#include "base/threading/non_thread_safe.h"
-
-typedef struct libusb_device* PlatformUsbDevice;
-typedef struct libusb_context* PlatformUsbContext;
-
-class UsbContext;
-class UsbDevice;
-
-// The USB service handles creating and managing an event handler thread that is
-// used to manage and dispatch USB events. It is also responsible for device
-// discovery on the system, which allows it to re-use device handles to prevent
-// competition for the same USB device.
-class UsbService : public base::MessageLoop::DestructionObserver,
-                   public base::NonThreadSafe {
- public:
-  typedef scoped_ptr<std::vector<scoped_refptr<UsbDevice> > >
-      ScopedDeviceVector;
-
-  // Must be called on FILE thread.
-  // Returns NULL when failed to initialized.
-  static UsbService* GetInstance();
-
-  scoped_refptr<UsbDevice> GetDeviceById(uint32 unique_id);
-
-  // Get all of the devices attached to the system, inserting them into
-  // |devices|. Clears |devices| before use. The result will be sorted by id
-  // in increasing order. Must be called on FILE thread.
-  void GetDevices(std::vector<scoped_refptr<UsbDevice> >* devices);
-
-  // base::MessageLoop::DestructionObserver implementation.
-  virtual void WillDestroyCurrentMessageLoop() OVERRIDE;
-
- private:
-  friend struct base::DefaultDeleter<UsbService>;
-
-  explicit UsbService(PlatformUsbContext context);
-  virtual ~UsbService();
-
-  // Enumerate USB devices from OS and Update devices_ map.
-  void RefreshDevices();
-
-  scoped_refptr<UsbContext> context_;
-
-  // TODO(ikarienator): Figure out a better solution.
-  uint32 next_unique_id_;
-
-  // The map from PlatformUsbDevices to UsbDevices.
-  typedef std::map<PlatformUsbDevice, scoped_refptr<UsbDevice> > DeviceMap;
-  DeviceMap devices_;
-
-  DISALLOW_COPY_AND_ASSIGN(UsbService);
-};
-
-#endif  // CHROME_BROWSER_USB_USB_SERVICE_H_