make one_shot_q an experiment

so it is configurable to faciliate testings

Change-Id: I247b62736c3a08ec2934793959d1ae605a05efa3

configure

@@ -251,6 +251,7 @@ EXPERIMENT_LIST="
     loop_dering
     implicit_compoundinter_weight
     scatterscan
+    oneshotq
 "
 CONFIG_LIST="
     external_build

vp9/encoder/vp9_onyx_int.h

@@ -30,10 +30,11 @@
 #include "vp9/encoder/vp9_lookahead.h"
 
 // Experimental rate control switches
-// #define ONE_SHOT_Q_ESTIMATE 1
-// #define STRICT_ONE_SHOT_Q 1
-// #define DISABLE_RC_LONG_TERM_MEM 1
-
+#if CONFIG_ONESHOTQ
+#define ONE_SHOT_Q_ESTIMATE 1
+#define STRICT_ONE_SHOT_Q 1
+#define DISABLE_RC_LONG_TERM_MEM 1
+#endif
 // #define SPEEDSTATS 1
 #define MIN_GF_INTERVAL             4
 #define DEFAULT_GF_INTERVAL         7