Implement basic USB device enumeration on Android.

device/usb/android/usb_jni_registrar.h

+// Copyright 2015 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_ANDROID_USB_JNI_REGISTRAR_H_
+#define DEVICE_USB_ANDROID_USB_JNI_REGISTRAR_H_
+
+#include <jni.h>
+
+namespace device {
+namespace android {
+
+// Registers C++ methods in device/usb classes with JNI.
+// See https://www.chromium.org/developers/design-documents/android-jni
+//
+// Must be called before classes in the USB module are used.
+bool RegisterUsbJni(JNIEnv* env);
+
+}  // namespace android
+}  // namespace device
+
+#endif  // DEVICE_USB_ANDROID_USB_JNI_REGISTRAR_H_