libmediadrm: API to set playback id

Bug: 159337195
Bug: 168341163
Test: GtsMediaTestCases MediaDrmTest#testSetPlaybackId
Change-Id: I9fad0ff83d465459443b018f589ccb78047aa71a
diff --git a/drm/libmediadrm/include/mediadrm/IDrm.h b/drm/libmediadrm/include/mediadrm/IDrm.h
index c117cec..ed71eee 100644
--- a/drm/libmediadrm/include/mediadrm/IDrm.h
+++ b/drm/libmediadrm/include/mediadrm/IDrm.h
@@ -152,6 +152,10 @@
             const char *mime,
             DrmPlugin::SecurityLevel securityLevel) const = 0;
 
+    virtual status_t setPlaybackId(
+            Vector<uint8_t> const &sessionId,
+            const char *playbackId) = 0;
+
 protected:
     IDrm() {}