Move frame allocations out of vp8_decode_frame()

in order to make it easier to implement the frame-base multithreading.

Change-Id: Iea2fd05be34fa704848fdc7669bf167f2ed229c5

vp8/decoder/onyxd_int.h

@@ -37,6 +37,8 @@ typedef struct VP8D_COMP
 {
     DECLARE_ALIGNED(16, MACROBLOCKD, mb);
 
+    YV12_BUFFER_CONFIG *dec_fb_ref[NUM_YV12_BUFFERS];
+
     DECLARE_ALIGNED(16, VP8_COMMON, common);
 
     vp8_reader bc, bc2;