Replace libusb in the Linux/Chrome OS USB I/O path.

device/usb/usb_device_impl.h

Index: device/usb/usb_device_impl.h
diff --git a/device/usb/usb_device_impl.h b/device/usb/usb_device_impl.h
index aea9b54cec1d138cc5d6dc27b57e96a88f1a934f..a5f36bab018c9e3aebb0059faa0a353362c9dfc0 100644
--- a/device/usb/usb_device_impl.h
+++ b/device/usb/usb_device_impl.h
@@ -13,6 +13,7 @@
 #include <utility>
 
 #include "base/callback.h"
+#include "base/files/scoped_file.h"
 #include "base/macros.h"
 #include "base/threading/thread_checker.h"
 #include "build/build_config.h"
@@ -74,6 +75,7 @@ class UsbDeviceImpl : public UsbDevice {
  protected:
   friend class UsbServiceImpl;
   friend class UsbDeviceHandleImpl;
+  friend class UsbDeviceHandleUsbfs;
 
   // Called by UsbServiceImpl only;
   UsbDeviceImpl(scoped_refptr<UsbContext> context,
@@ -90,7 +92,8 @@ class UsbDeviceImpl : public UsbDevice {
   void ReadAllConfigurations();
 
   // Called by UsbDeviceHandleImpl.
-  void HandleClosed(scoped_refptr<UsbDeviceHandle> handle);
+  void HandleClosed(UsbDeviceHandle* handle);
+  void ActiveConfigurationChanged(int configuration_value);
   void RefreshActiveConfiguration();
 
  private:
@@ -103,10 +106,15 @@ class UsbDeviceImpl : public UsbDevice {
                           const std::string& error_message);
   void OpenOnBlockingThreadWithFd(dbus::FileDescriptor fd,
                                   const OpenCallback& callback);
-#endif
+#else
   void OpenOnBlockingThread(const OpenCallback& callback);
+#endif  // defined(OS_CHROMEOS)
+#if defined(OS_LINUX)
+  void Opened(base::ScopedFD fd, const OpenCallback& callback);
+#else
   void Opened(PlatformUsbDeviceHandle platform_handle,
               const OpenCallback& callback);
+#endif  // defined(OS_LINUX)
 
   base::ThreadChecker thread_checker_;
   PlatformUsbDevice platform_device_;