vp9_decodeframe.h: add missing include

Change-Id: I8ef772a016a79cab88bee8e9739530aa030baaa9
diff --git a/vp9/decoder/vp9_decodeframe.h b/vp9/decoder/vp9_decodeframe.h
index 05af706..ce33cbd 100644
--- a/vp9/decoder/vp9_decodeframe.h
+++ b/vp9/decoder/vp9_decodeframe.h
@@ -16,6 +16,8 @@
 extern "C" {
 #endif
 
+#include "vp9/common/vp9_enums.h"
+
 struct VP9Decoder;
 struct vpx_read_bit_buffer;