Add missing include

Change-Id: I00181029e80a2ba75320550c14e950fadbab8a64
diff --git a/include/gui/SurfaceTexture.h b/include/gui/SurfaceTexture.h
index 140fbed..2e2c74c 100644
--- a/include/gui/SurfaceTexture.h
+++ b/include/gui/SurfaceTexture.h
@@ -17,6 +17,8 @@
 #ifndef ANDROID_GUI_SURFACETEXTURE_H
 #define ANDROID_GUI_SURFACETEXTURE_H
 
+#include <ui/GraphicBuffer.h>
+
 namespace android {
 
 struct SurfaceTexture {