Bug 1548795 - P1. Don't use StaticPrefs in GPU process. r=mattwoodrow

Differential Revision: https://phabricator.services.mozilla.com/D29984

--HG--
extra : moz-landing-system : lando

dom/media/platforms/wmf/WMFDecoderModule.cpp

@@ -90,7 +90,7 @@ void WMFDecoderModule::Init() {
 
   sDXVAEnabled = sDXVAEnabled && gfx::gfxVars::CanUseHardwareVideoDecoding();
   testForVPx = testForVPx && gfx::gfxVars::CanUseHardwareVideoDecoding();
-  if (testForVPx && StaticPrefs::MediaWmfVp9Enabled()) {
+  if (testForVPx && gfxPrefs::MediaWmfVp9Enabled()) {
     gfx::WMFVPXVideoCrashGuard guard;
     if (!guard.Crashed()) {
       sUsableVPXMFT = CanCreateMFTDecoder(CLSID_WebmMfVpxDec);

gfx/thebes/gfxPrefs.h

@@ -741,7 +741,8 @@ class gfxPrefs final {
   DECL_GFX_PREF(Live, "media.wmf.skip-blacklist", PDMWMFSkipBlacklist, bool, false);
   DECL_GFX_PREF(Live, "media.wmf.deblacklisting-for-telemetry-in-gpu-process", PDMWMFDeblacklistingForTelemetryInGPUProcess, bool, false);
   DECL_GFX_PREF(Live, "media.wmf.amd.highres.enabled", PDMWMFAMDHighResEnabled, bool, true);
-  DECL_GFX_PREF(Live, "media.wmf.allow-unsupported-resolutions",  PDMWMFAllowUnsupportedResolutions, bool, false);
+  DECL_GFX_PREF(Live, "media.wmf.allow-unsupported-resolutions", PDMWMFAllowUnsupportedResolutions, bool, false);
+  DECL_GFX_PREF(Once, "media.wmf.vp9.enabled", MediaWmfVp9Enabled, bool, true);
 #endif
 
   // These affect how line scrolls from wheel events will be accelerated.

modules/libpref/init/StaticPrefList.h

@@ -1798,12 +1798,6 @@ VARCACHE_PREF(
   bool, false
 )
 
-VARCACHE_PREF(
-  "media.wmf.vp9.enabled",
-   MediaWmfVp9Enabled,
-  RelaxedAtomicBool, true
-)
-
 #endif // MOZ_WMF
 
 // Whether to check the decoder supports recycling.