Use aidl interface for Widevine service.

The interface is defined in
hardware/interfaces/drm/aidl(http://go/ag/15329852).

Test: build
  m android.hardware.drm-service.widevine -j128

Test: build_and_run_all_unit_tests.sh
  for hidl tests

Test: atest VtsAidlHalDrmTargetTest

Test:   atest vts_treble_vintf_vendor_test:vts_treble_vintf_vendor_test.DeviceManifest/SingleManifestTest#ManifestAidlHalsServed/0 -- --abi x86_64

Bug: 200055138
Bug: 170964303
Change-Id: I5654d90d8a4b0bae4b4a78e79b27c1cafec36be7

libwvdrmengine/aidl_include/WVCreatePluginFactories.h

@@ -0,0 +1,26 @@
+//
+// Copyright 2021 Google LLC. All Rights Reserved. This file and proprietary
+// source code may only be used and distributed under the Widevine License
+// Agreement.
+//
+
+#ifndef WV_CREATE_PLUGIN_FACTORIES_H_
+#define WV_CREATE_PLUGIN_FACTORIES_H_
+
+#include "WVCryptoFactory.h"
+#include "WVDrmFactory.h"
+
+namespace wvdrm {
+namespace hardware {
+namespace drm {
+namespace widevine {
+
+std::shared_ptr<WVDrmFactory> createDrmFactory();
+std::shared_ptr<WVCryptoFactory> createCryptoFactory();
+
+}  // namespace widevine
+}  // namespace drm
+}  // namespace hardware
+}  // namespace wvdrm
+
+#endif  // WV_CREATE_PLUGIN_FACTORIES_H_