fix for b/4126624 Widevine DRM client not sending heartbeats

Added some missing parameters to the heartbeat message, found in end-to-end
testing with youtube.  Also enabled heartbeats on client builds.

Change-Id: I445fb0cb168e63a041f0ecf828eaad493143a648

proprietary/drmwvmplugin/src/WVMDrmPlugin.cpp

@@ -178,6 +178,18 @@ bool WVMDrmPlugin::SendEvent(WVDRMPluginAPI::EventType type,
     case WVDRMPluginAPI::EventType_HeartbeatPeriod:
         code = MessageType_HeartbeatPeriod;
         break;
+    case WVDRMPluginAPI::EventType_AssetId:
+        code = MessageType_AssetId;
+        break;
+    case WVDRMPluginAPI::EventType_DeviceId:
+        code = MessageType_DeviceId;
+        break;
+    case WVDRMPluginAPI::EventType_StreamId:
+        code = MessageType_StreamId;
+        break;
+    case WVDRMPluginAPI::EventType_UserData:
+        code = MessageType_UserData;
+        break;
     default:
         break;
     }