HLS media playlist EXT-X-KEY format changes

[ Merged of http://go/wvgerrit/16576 ]

The WV EXT-X-KEY attribute list earlier expected a cenc PSSH box in the
URI field, in a hexadecimal sequence format. To ease the burden on
content providers, the URI field will now contain init data in a json
format and base64 encoded. The platform will assume responsibility
to parse this data and create a widevine init data protobuf that
can be included in the license request.

b/20630275

Change-Id: I49e270bedbe96791fc9b282214a9a358d95d163e

libwvdrmengine/cdm/core/src/license_protocol.proto

@@ -547,3 +547,42 @@ message SignedCertificateStatusList {
   // key using RSASSA-PSS. Required.
   optional bytes signature = 2;
 }
+
+// ----------------------------------------------------------------------------
+// widevine_header.proto
+// ----------------------------------------------------------------------------
+// Copyright 2016 Google Inc. All Rights Reserved.
+//
+// Description:
+//   Public protocol buffer definitions for Widevine Cenc Header
+//   protocol.
+message WidevineCencHeader {
+  enum Algorithm {
+    UNENCRYPTED = 0;
+    AESCTR = 1;
+  };
+  optional Algorithm algorithm = 1;
+  repeated bytes key_id = 2;
+
+  // Content provider name.
+  optional string provider = 3;
+
+  // A content identifier, specified by content provider.
+  optional bytes content_id = 4;
+
+  // Track type. Acceptable values are SD, HD and AUDIO. Used to differentiate
+  // content keys used by an asset.
+  // No longer adding track_type to the PSSH since the Widevine license server
+  // will return keys for all allowed track types in a single license.
+  optional string track_type_deprecated = 5;
+
+  // The name of a registered policy to be used for this asset.
+  optional string policy = 6;
+
+  // Crypto period index, for media using key rotation.
+  optional uint32 crypto_period_index = 7;
+
+  // Optional protected context for group content. The grouped_license is a
+  // serialized SignedMessage.
+  optional bytes grouped_license = 8;
+}