Bug 1263839: P2. Force re-run of VP9 benchmark based on a version check. r=kentuckyfriedtakahe

The version number is to be manually updated when we want to re-run the test (like improvement in ffvp9 or libvpx)

MozReview-Commit-ID: 9KzYCGWvIpp

--HG--
extra : rebase_source : a5c06065d3e174f3a4cb5ca0fbe2b08b8728f083

dom/ipc/ContentParent.cpp

@@ -5717,6 +5717,8 @@ ContentParent::RecvNotifyBenchmarkResult(const nsString& aCodecName,
 {
   if (aCodecName.EqualsLiteral("VP9")) {
     Preferences::SetUint(VP9Benchmark::sBenchmarkFpsPref, aDecodeFPS);
+    Preferences::SetUint(VP9Benchmark::sBenchmarkFpsVersionCheck,
+                         VP9Benchmark::sBenchmarkVersionID);
   }
   return true;
 }

dom/media/Benchmark.cpp

@@ -16,7 +16,12 @@
 
 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 = 1;
+
 const char* VP9Benchmark::sBenchmarkFpsPref = "media.benchmark.vp9.fps";
+const char* VP9Benchmark::sBenchmarkFpsVersionCheck = "media.benchmark.vp9.versioncheck";
 bool VP9Benchmark::sHasRunTest = false;
 
 bool
@@ -25,8 +30,9 @@ VP9Benchmark::IsVP9DecodeFast()
   MOZ_ASSERT(NS_IsMainThread());
 
   bool hasPref = Preferences::HasUserValue(sBenchmarkFpsPref);
+  uint32_t hadRecentUpdate = Preferences::GetUint(sBenchmarkFpsVersionCheck, 0U);
 
-  if (!sHasRunTest && !hasPref) {
+  if (!sHasRunTest && (!hasPref || hadRecentUpdate != sBenchmarkVersionID)) {
     sHasRunTest = true;
 
     RefPtr<WebMDemuxer> demuxer =
@@ -54,6 +60,7 @@ VP9Benchmark::IsVP9DecodeFast()
           }
         } else {
           Preferences::SetUint(sBenchmarkFpsPref, aDecodeFps);
+          Preferences::SetUint(sBenchmarkFpsVersionCheck, sBenchmarkVersionID);
         }
         Telemetry::Accumulate(Telemetry::ID::VIDEO_VP9_BENCHMARK_FPS, aDecodeFps);
       },

dom/media/Benchmark.h

@@ -104,6 +104,8 @@ class VP9Benchmark
 public:
   static bool IsVP9DecodeFast();
   static const char* sBenchmarkFpsPref;
+  static const char* sBenchmarkFpsVersionCheck;
+  static const uint32_t sBenchmarkVersionID;
   static bool sHasRunTest;
 };
 }