Bug 1261129: Make VP9 sample data const. r=kentuckyfriedtakahe

MozReview-Commit-ID: 1VhEkxqLInz

--HG--
extra : rebase_source : 2915047cba83971618329a3f471e0a8e541dfe62

dom/media/WebMSample.h

@@ -1,4 +1,4 @@
-static uint8_t sWebMSample[] = {
+static const uint8_t sWebMSample[] = {
   0x1a, 0x45, 0xdf, 0xa3, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x1f, 0x42,
   0x86, 0x81, 0x01, 0x42, 0xf7, 0x81, 0x01, 0x42, 0xf2, 0x81, 0x04, 0x42, 0xf3,
   0x81, 0x08, 0x42, 0x82, 0x84, 0x77, 0x65, 0x62, 0x6d, 0x42, 0x87, 0x81, 0x02,