Specify widevine/media_cas_packager_sdk/presubmit in media_cas_packager_sdk METADATA file.

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Moves ecm_generator to media_cas_packager_sdk/internal.

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Add a simple TCP server listening on a port. My intention is to use this server to support the Simulcrypt APIs (TODO).

Also add a simple TCP client binary for testing the server and also demo how to call the Simulcrypt APIs (TODO).

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If only a single key is in the ECM, it is the EVEN key. To make the code matches this understanding, change a parameter from 'false' to 'true'. But this change has NO impact on the produced ECM, regardless this parameter is 'false' or 'true' (i.e., whether using push_front or push_back), only a single key is in the ECM.

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Add classes that process Simulcrypt ECMG messages
1) Stream_set-up
2) CW_provision

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Renames server and client binaries.

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Make ecmg call ecm_generator to generate ecm. The return of the ecm to Simulcrypt caller will be implemented in the next CL.

For now, using the 'key' (control word) in CW_provision message also as the 'key_id'.

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Move common folder

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=217358698

common/widevine_system_id.h

@@ -0,0 +1,22 @@
+////////////////////////////////////////////////////////////////////////////////
+// Copyright 2017 Google LLC.
+//
+// This software is licensed under the terms defined in the Widevine Master
+// License Agreement. For a copy of this agreement, please contact
+// widevine-licensing@google.com.
+////////////////////////////////////////////////////////////////////////////////
+//
+// Common Encryption (CENC) system ID for Widevine DRM.
+
+#ifndef COMMON_WIDEVINE_SYSTEM_ID_H_
+#define COMMON_WIDEVINE_SYSTEM_ID_H_
+
+#include <cstdint>
+
+namespace widevine {
+
+extern const uint8_t kWidevineSystemId[16];
+
+}  // namespace widevine
+
+#endif  // COMMON_WIDEVINE_SYSTEM_ID_H_