Add support for sending a USB SET_CONFIGURATION request.

device/usb/usb_device_impl.h

 // 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.
 
 #ifndef DEVICE_USB_USB_DEVICE_IMPL_H_
 #define DEVICE_USB_USB_DEVICE_IMPL_H_
 
 #include <vector>
 
 #include "base/basictypes.h"
@@ skipping 20 matching lines @@
 class UsbDeviceImpl : public UsbDevice {
  public:
 // UsbDevice implementation:
 #if defined(OS_CHROMEOS)
   virtual void RequestUsbAccess(
       int interface_id,
       const base::Callback<void(bool success)>& callback) override;
 #endif  // OS_CHROMEOS
   scoped_refptr<UsbDeviceHandle> Open() override;
   bool Close(scoped_refptr<UsbDeviceHandle> handle) override;
-  const UsbConfigDescriptor& GetConfiguration() override;
+  const UsbConfigDescriptor* GetConfiguration() override;
   bool GetManufacturer(base::string16* manufacturer) override;
   bool GetProduct(base::string16* product) override;
   bool GetSerialNumber(base::string16* serial_number) override;
 
  protected:
   friend class UsbServiceImpl;
+  friend class UsbDeviceHandleImpl;
 
   // Called by UsbServiceImpl only;
   UsbDeviceImpl(scoped_refptr<UsbContext> context,
                 scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner,
                 PlatformUsbDevice platform_device,
                 uint16 vendor_id,
                 uint16 product_id,
                 uint32 unique_id);
 
   ~UsbDeviceImpl() override;
 
-  // Called only by UsbService.
+  // Called only by UsbServiceImpl.
   void OnDisconnect();
 
+  // Called by UsbDeviceHandleImpl.
+  void RefreshConfiguration();
+
  private:
   base::ThreadChecker thread_checker_;
   PlatformUsbDevice platform_device_;
 
   // On Linux these properties are read from sysfs when the device is enumerated
   // to avoid hitting the permission broker on Chrome OS for a real string
   // descriptor request.
   base::string16 manufacturer_;
   base::string16 product_;
   base::string16 serial_number_;
 #if !defined(USE_UDEV)
   // On other platforms the device must be opened in order to cache them. This
   // should be delayed until the strings are needed to avoid poor interactions
   // with other applications.
   void CacheStrings();
   bool strings_cached_;
 #endif
 #if defined(OS_CHROMEOS)
   // On Chrome OS save the devnode string for requesting path access from
   // permission broker.
   std::string devnode_;
 #endif
 
-  // The active configuration descriptor is not read immediately but cached for
-  // later use.
-  bool current_configuration_cached_;
-  UsbConfigDescriptor current_configuration_;
+  // The current device configuration descriptor. May be null if the device is
+  // in an unconfigured state.
+  scoped_ptr<UsbConfigDescriptor> configuration_;
 
   // Retain the context so that it will not be released before UsbDevice.
   scoped_refptr<UsbContext> context_;
 
   // Opened handles.
   typedef std::vector<scoped_refptr<UsbDeviceHandleImpl> > HandlesVector;
   HandlesVector handles_;
 
   // Reference to the UI thread for permission-broker calls.
   scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner_;
 
   DISALLOW_COPY_AND_ASSIGN(UsbDeviceImpl);
 };
 
 }  // namespace device
 
 #endif  // DEVICE_USB_USB_DEVICE_IMPL_H_