drm_hwcomposer: Split gralloc out into an importer

Add the concept of an importer so we can plug in different
sources of bo.

Signed-off-by: Sean Paul <seanpaul@chromium.org>
Change-Id: I4f741ef4fa7c44e9cb31db61a146aed273854a69
diff --git a/Android.mk b/Android.mk
index 2eb3212..efc78ce 100644
--- a/Android.mk
+++ b/Android.mk
@@ -16,6 +16,9 @@
 LOCAL_PATH := $(call my-dir)
 include $(CLEAR_VARS)
 
+# TODO: We should specify this in device.mk
+BUFFER_IMPORTER := gralloc
+
 LOCAL_SHARED_LIBRARIES := \
 	libdrm \
 	libhardware \
@@ -32,6 +35,12 @@
 
 LOCAL_CFLAGS :=
 LOCAL_SRC_FILES := hwcomposer.cpp
+
+ifeq ($(strip $(BUFFER_IMPORTER)),gralloc)
+LOCAL_C_INCLUDES += external/drm_gralloc
+LOCAL_SRC_FILES += hwcomposer_import_drm_gralloc.cpp
+endif
+
 LOCAL_MODULE := hwcomposer.drm
 LOCAL_MODULE_TAGS := optional
 LOCAL_MODULE_RELATIVE_PATH := hw