drm_hwcomposer: Add Worker class to abstract thread nasties

This will allow us to spin up threads more easily.

Change-Id: I74add3d20ab14a61f3c646877a3ee17d0bd99ac4
Signed-off-by: Sean Paul <seanpaul@chromium.org>
diff --git a/Android.mk b/Android.mk
index 0b8f1ad..58bf1ef 100644
--- a/Android.mk
+++ b/Android.mk
@@ -44,7 +44,8 @@
 	drmmode.cpp \
 	drmplane.cpp \
 	drmproperty.cpp \
-	hwcomposer.cpp
+	hwcomposer.cpp \
+	worker.cpp
 
 ifeq ($(strip $(BUFFER_IMPORTER)),drm-gralloc)
 LOCAL_C_INCLUDES += external/drm_gralloc