Bug 1845143 - part2 : remove the pref 'media.wmf.low-latency.force-disabled'. r=media-playback-reviewers,chunmin

Having the pref `media.wmf.low-latency.enabled` is enough.

Differential Revision: https://phabricator.services.mozilla.com/D184395

dom/media/ipc/MFMediaEngineParent.cpp

@@ -161,9 +161,7 @@ void MFMediaEngineParent::CreateMediaEngine() {
   RETURN_VOID_IF_FAILED(CoCreateInstance(CLSID_MFMediaEngineClassFactory,
                                          nullptr, CLSCTX_INPROC_SERVER,
                                          IID_PPV_ARGS(&factory)));
-  const bool isLowLatency =
-      StaticPrefs::media_wmf_low_latency_enabled() &&
-      !StaticPrefs::media_wmf_low_latency_force_disabled();
+  const bool isLowLatency = StaticPrefs::media_wmf_low_latency_enabled();
   static const DWORD MF_MEDIA_ENGINE_DEFAULT = 0;
   RETURN_VOID_IF_FAILED(factory->CreateInstance(
       isLowLatency ? MF_MEDIA_ENGINE_REAL_TIME_MODE : MF_MEDIA_ENGINE_DEFAULT,

dom/media/platforms/wmf/WMFVideoMFTManager.cpp

@@ -325,8 +325,7 @@ MediaResult WMFVideoMFTManager::InitInternal() {
     attr->SetUINT32(CODECAPI_AVDecNumWorkerThreads,
                     WMFDecoderModule::GetNumDecoderThreads());
     bool lowLatency =
-        (StaticPrefs::media_wmf_low_latency_enabled() || IsWin10OrLater()) &&
-        !StaticPrefs::media_wmf_low_latency_force_disabled();
+        (StaticPrefs::media_wmf_low_latency_enabled() || IsWin10OrLater());
     if (mLowLatency || lowLatency) {
       hr = attr->SetUINT32(CODECAPI_AVLowLatencyMode, TRUE);
       if (SUCCEEDED(hr)) {

modules/libpref/init/StaticPrefList.yaml

@@ -10186,11 +10186,6 @@
     value: true
     mirror: always
 
--   name: media.wmf.low-latency.force-disabled
-    type: RelaxedAtomicBool
-    value: false
-    mirror: always
-
 -   name: media.wmf.skip-blacklist
     type: RelaxedAtomicBool
     value: false