OEMCrypto Query Key Control Block

Merge from Widevine repo http://go/wvgerrit/13818

This CL adds the ability to query OEMCrypto about the key control
block and duration of a key that has been loaded.  There are unit
tests and implementation in the level 3 and reference implementation.

b/18503541

Change-Id: I8e40d90a3c64c1ce030af6fef9e98c8eac0df1a5

libwvdrmengine/oemcrypto/mock/src/oemcrypto_engine_mock.h

@@ -167,6 +167,7 @@ class SessionContext {
                   const std::vector<uint8_t>& key_control_iv);
   bool UpdateMacKeys(const std::vector<uint8_t>& mac_keys,
                      const std::vector<uint8_t>& iv);
+  bool QueryKeyControlBlock(const KeyId& key_id, uint32_t* data);
   bool SelectContentKey(const KeyId& key_id);
   const Key* current_content_key(void) {return current_content_key_;}
   void set_mac_key_server(const std::vector<uint8_t>& mac_key_server) {