Bug 1461268 - P2. Bump benchmark version ID. r=bryce

This will force the benchmark to be re-run, following de-activation of the AMD VP9 decoder.

MozReview-Commit-ID: KwwoQNfSJ4t

--HG--
extra : rebase_source : 4edc750d448d6f023a645457edcbd138974c7d9a

dom/media/Benchmark.cpp

@@ -31,7 +31,7 @@ namespace mozilla {
 
 // Update this version number to force re-running the benchmark. Such as when
 // an improvement to FFVP9 or LIBVPX is deemed worthwhile.
-const uint32_t VP9Benchmark::sBenchmarkVersionID = 3;
+const uint32_t VP9Benchmark::sBenchmarkVersionID = 4;
 
 const char* VP9Benchmark::sBenchmarkFpsPref = "media.benchmark.vp9.fps";
 const char* VP9Benchmark::sBenchmarkFpsVersionCheck = "media.benchmark.vp9.versioncheck";