Fix possible infinite loop when purging textures.

Change-Id: Ib05b398ae03e734da2dab0496df416fed4570b1c
diff --git a/libs/hwui/PatchCache.h b/libs/hwui/PatchCache.h
index e874a16..6dad831 100644
--- a/libs/hwui/PatchCache.h
+++ b/libs/hwui/PatchCache.h
@@ -17,6 +17,8 @@
 #ifndef ANDROID_UI_PATCH_CACHE_H
 #define ANDROID_UI_PATCH_CACHE_H
 
+#include <utils/ResourceTypes.h>
+
 #include "Patch.h"
 #include "GenerationCache.h"