diff -up firefox-99.0/gfx/gl/GLContextEGL.h.D142257 firefox-99.0/gfx/gl/GLContextEGL.h
--- firefox-99.0/gfx/gl/GLContextEGL.h.D142257	2022-03-31 01:24:45.000000000 +0200
+++ firefox-99.0/gfx/gl/GLContextEGL.h	2022-04-06 10:32:53.287145554 +0200
@@ -21,11 +21,9 @@ class CompositorWidget;
 }  // namespace widget
 namespace gl {
 
-RefPtr<GLLibraryEGL> DefaultEglLibrary(nsACString* const out_failureId);
-
 inline std::shared_ptr<EglDisplay> DefaultEglDisplay(
     nsACString* const out_failureId) {
-  const auto lib = DefaultEglLibrary(out_failureId);
+  const auto lib = GLLibraryEGL::Get(out_failureId);
   if (!lib) {
     return nullptr;
   }
diff -up firefox-99.0/gfx/gl/GLContextProviderEGL.cpp.D142257 firefox-99.0/gfx/gl/GLContextProviderEGL.cpp
--- firefox-99.0/gfx/gl/GLContextProviderEGL.cpp.D142257	2022-03-31 01:24:50.000000000 +0200
+++ firefox-99.0/gfx/gl/GLContextProviderEGL.cpp	2022-04-06 10:34:20.468017966 +0200
@@ -237,7 +237,7 @@ class GLContextEGLFactory {
 already_AddRefed<GLContext> GLContextEGLFactory::CreateImpl(
     EGLNativeWindowType aWindow, bool aHardwareWebRender, bool aUseGles) {
   nsCString failureId;
-  const auto lib = gl::DefaultEglLibrary(&failureId);
+  const auto lib = GLLibraryEGL::Get(&failureId);
   if (!lib) {
     gfxCriticalNote << "Failed[3] to load EGL library: " << failureId.get();
     return nullptr;
@@ -1209,32 +1209,8 @@ already_AddRefed<GLContext> GLContextPro
 /*static*/
 GLContext* GLContextProviderEGL::GetGlobalContext() { return nullptr; }
 
-// -
-
-static StaticMutex sMutex;
-static StaticRefPtr<GLLibraryEGL> gDefaultEglLibrary;
-
-RefPtr<GLLibraryEGL> DefaultEglLibrary(nsACString* const out_failureId) {
-  StaticMutexAutoLock lock(sMutex);
-  if (!gDefaultEglLibrary) {
-    gDefaultEglLibrary = GLLibraryEGL::Create(out_failureId);
-    if (!gDefaultEglLibrary) {
-      NS_WARNING("GLLibraryEGL::Create failed");
-    }
-  }
-  return gDefaultEglLibrary.get();
-}
-
-// -
-
 /*static*/
-void GLContextProviderEGL::Shutdown() {
-  StaticMutexAutoLock lock(sMutex);
-  if (!gDefaultEglLibrary) {
-    return;
-  }
-  gDefaultEglLibrary = nullptr;
-}
+void GLContextProviderEGL::Shutdown() { GLLibraryEGL::Shutdown(); }
 
 } /* namespace gl */
 } /* namespace mozilla */
diff -up firefox-99.0/gfx/gl/GLLibraryEGL.cpp.D142257 firefox-99.0/gfx/gl/GLLibraryEGL.cpp
--- firefox-99.0/gfx/gl/GLLibraryEGL.cpp.D142257	2022-03-31 01:24:45.000000000 +0200
+++ firefox-99.0/gfx/gl/GLLibraryEGL.cpp	2022-04-06 10:32:53.288145587 +0200
@@ -48,6 +48,9 @@
 namespace mozilla {
 namespace gl {
 
+StaticMutex GLLibraryEGL::sMutex;
+StaticRefPtr<GLLibraryEGL> GLLibraryEGL::sInstance;
+
 // should match the order of EGLExtensions, and be null-terminated.
 static const char* sEGLLibraryExtensionNames[] = {
     "EGL_ANDROID_get_native_client_buffer", "EGL_ANGLE_device_creation",
@@ -140,15 +143,17 @@ static PRLibrary* LoadLibraryForEGLOnWin
 
 #endif  // XP_WIN
 
-static std::shared_ptr<EglDisplay> GetAndInitDisplay(GLLibraryEGL& egl,
-                                                     void* displayType) {
+static std::shared_ptr<EglDisplay> GetAndInitDisplay(
+    GLLibraryEGL& egl, void* displayType,
+    const StaticMutexAutoLock& aProofOfLock) {
   const auto display = egl.fGetDisplay(displayType);
   if (!display) return nullptr;
-  return EglDisplay::Create(egl, display, false);
+  return EglDisplay::Create(egl, display, false, aProofOfLock);
 }
 
-static std::shared_ptr<EglDisplay> GetAndInitWARPDisplay(GLLibraryEGL& egl,
-                                                         void* displayType) {
+static std::shared_ptr<EglDisplay> GetAndInitWARPDisplay(
+    GLLibraryEGL& egl, void* displayType,
+    const StaticMutexAutoLock& aProofOfLock) {
   const EGLAttrib attrib_list[] = {
       LOCAL_EGL_PLATFORM_ANGLE_DEVICE_TYPE_ANGLE,
       LOCAL_EGL_PLATFORM_ANGLE_DEVICE_TYPE_WARP_ANGLE,
@@ -167,11 +172,12 @@ static std::shared_ptr<EglDisplay> GetAn
     return nullptr;
   }
 
-  return EglDisplay::Create(egl, display, true);
+  return EglDisplay::Create(egl, display, true, aProofOfLock);
 }
 
 std::shared_ptr<EglDisplay> GLLibraryEGL::CreateDisplay(
     ID3D11Device* const d3d11Device) {
+  StaticMutexAutoLock lock(sMutex);
   EGLDeviceEXT eglDevice =
       fCreateDeviceANGLE(LOCAL_EGL_D3D11_DEVICE_ANGLE, d3d11Device, nullptr);
   if (!eglDevice) {
@@ -199,7 +205,7 @@ std::shared_ptr<EglDisplay> GLLibraryEGL
     return nullptr;
   }
 
-  const auto ret = EglDisplay::Create(*this, display, false);
+  const auto ret = EglDisplay::Create(*this, display, false, lock);
 
   if (!ret) {
     const EGLint err = fGetError();
@@ -263,7 +269,8 @@ class AngleErrorReporting {
 AngleErrorReporting gAngleErrorReporter;
 
 static std::shared_ptr<EglDisplay> GetAndInitDisplayForAccelANGLE(
-    GLLibraryEGL& egl, nsACString* const out_failureId) {
+    GLLibraryEGL& egl, nsACString* const out_failureId,
+    const StaticMutexAutoLock& aProofOfLock) {
   gfx::FeatureState& d3d11ANGLE =
       gfx::gfxConfig::GetFeature(gfx::Feature::D3D11_HW_ANGLE);
 
@@ -285,16 +292,18 @@ static std::shared_ptr<EglDisplay> GetAn
   });
 
   if (gfx::gfxConfig::IsForcedOnByUser(gfx::Feature::D3D11_HW_ANGLE)) {
-    return GetAndInitDisplay(egl, LOCAL_EGL_D3D11_ONLY_DISPLAY_ANGLE);
+    return GetAndInitDisplay(egl, LOCAL_EGL_D3D11_ONLY_DISPLAY_ANGLE,
+                             aProofOfLock);
   }
 
   std::shared_ptr<EglDisplay> ret;
   if (d3d11ANGLE.IsEnabled()) {
-    ret = GetAndInitDisplay(egl, LOCAL_EGL_D3D11_ELSE_D3D9_DISPLAY_ANGLE);
+    ret = GetAndInitDisplay(egl, LOCAL_EGL_D3D11_ELSE_D3D9_DISPLAY_ANGLE,
+                            aProofOfLock);
   }
 
   if (!ret) {
-    ret = GetAndInitDisplay(egl, EGL_DEFAULT_DISPLAY);
+    ret = GetAndInitDisplay(egl, EGL_DEFAULT_DISPLAY, aProofOfLock);
   }
 
   if (!ret && out_failureId->IsEmpty()) {
@@ -326,12 +335,20 @@ Maybe<SymbolLoader> GLLibraryEGL::GetSym
 // -
 
 /* static */
-RefPtr<GLLibraryEGL> GLLibraryEGL::Create(nsACString* const out_failureId) {
-  RefPtr<GLLibraryEGL> ret = new GLLibraryEGL;
-  if (!ret->Init(out_failureId)) {
-    return nullptr;
+RefPtr<GLLibraryEGL> GLLibraryEGL::Get(nsACString* const out_failureId) {
+  StaticMutexAutoLock lock(sMutex);
+  if (!sInstance) {
+    sInstance = new GLLibraryEGL;
+    if (NS_WARN_IF(!sInstance->Init(out_failureId))) {
+      sInstance = nullptr;
+    }
   }
-  return ret;
+  return sInstance;
+}
+
+/* static */ void GLLibraryEGL::Shutdown() {
+  StaticMutexAutoLock lock(sMutex);
+  sInstance = nullptr;
 }
 
 bool GLLibraryEGL::Init(nsACString* const out_failureId) {
@@ -640,9 +657,9 @@ static void MarkExtensions(const char* r
 // -
 
 // static
-std::shared_ptr<EglDisplay> EglDisplay::Create(GLLibraryEGL& lib,
-                                               const EGLDisplay display,
-                                               const bool isWarp) {
+std::shared_ptr<EglDisplay> EglDisplay::Create(
+    GLLibraryEGL& lib, const EGLDisplay display, const bool isWarp,
+    const StaticMutexAutoLock& aProofOfLock) {
   // Retrieve the EglDisplay if it already exists
   {
     const auto itr = lib.mActiveDisplays.find(display);
@@ -710,6 +727,7 @@ EglDisplay::EglDisplay(const PrivateUseO
 }
 
 EglDisplay::~EglDisplay() {
+  StaticMutexAutoLock lock(GLLibraryEGL::sMutex);
   fTerminate();
   mLib->mActiveDisplays.erase(mDisplay);
 }
@@ -718,16 +736,24 @@ EglDisplay::~EglDisplay() {
 
 std::shared_ptr<EglDisplay> GLLibraryEGL::DefaultDisplay(
     nsACString* const out_failureId) {
+  StaticMutexAutoLock lock(sMutex);
   auto ret = mDefaultDisplay.lock();
   if (ret) return ret;
 
-  ret = CreateDisplay(false, out_failureId);
+  ret = CreateDisplayLocked(false, out_failureId, lock);
   mDefaultDisplay = ret;
   return ret;
 }
 
 std::shared_ptr<EglDisplay> GLLibraryEGL::CreateDisplay(
     const bool forceAccel, nsACString* const out_failureId) {
+  StaticMutexAutoLock lock(sMutex);
+  return CreateDisplayLocked(forceAccel, out_failureId, lock);
+}
+
+std::shared_ptr<EglDisplay> GLLibraryEGL::CreateDisplayLocked(
+    const bool forceAccel, nsACString* const out_failureId,
+    const StaticMutexAutoLock& aProofOfLock) {
   std::shared_ptr<EglDisplay> ret;
 
   if (IsExtensionSupported(EGLLibExtension::ANGLE_platform_angle_d3d)) {
@@ -747,7 +773,7 @@ std::shared_ptr<EglDisplay> GLLibraryEGL
 
     // Hardware accelerated ANGLE path (supported or force accel)
     if (shouldTryAccel) {
-      ret = GetAndInitDisplayForAccelANGLE(*this, out_failureId);
+      ret = GetAndInitDisplayForAccelANGLE(*this, out_failureId, aProofOfLock);
     }
 
     // Report the acceleration status to telemetry
@@ -766,7 +792,7 @@ std::shared_ptr<EglDisplay> GLLibraryEGL
 
     // Fallback to a WARP display if ANGLE fails, or if WARP is forced
     if (!ret && shouldTryWARP) {
-      ret = GetAndInitWARPDisplay(*this, EGL_DEFAULT_DISPLAY);
+      ret = GetAndInitWARPDisplay(*this, EGL_DEFAULT_DISPLAY, aProofOfLock);
       if (!ret) {
         if (out_failureId->IsEmpty()) {
           *out_failureId = "FEATURE_FAILURE_WARP_FALLBACK"_ns;
@@ -788,7 +814,7 @@ std::shared_ptr<EglDisplay> GLLibraryEGL
       }
     }
 #endif
-    ret = GetAndInitDisplay(*this, nativeDisplay);
+    ret = GetAndInitDisplay(*this, nativeDisplay, aProofOfLock);
   }
 
   if (!ret) {
diff -up firefox-99.0/gfx/gl/GLLibraryEGL.h.D142257 firefox-99.0/gfx/gl/GLLibraryEGL.h
--- firefox-99.0/gfx/gl/GLLibraryEGL.h.D142257	2022-03-31 01:24:50.000000000 +0200
+++ firefox-99.0/gfx/gl/GLLibraryEGL.h	2022-04-06 10:32:53.288145587 +0200
@@ -13,6 +13,8 @@
 #include "mozilla/EnumTypeTraits.h"
 #include "mozilla/Maybe.h"
 #include "mozilla/RefPtr.h"
+#include "mozilla/StaticMutex.h"
+#include "mozilla/StaticPtr.h"
 #include "nsISupports.h"
 #include "prlink.h"
 
@@ -125,14 +127,22 @@ class GLLibraryEGL final {
   std::unordered_map<EGLDisplay, std::weak_ptr<EglDisplay>> mActiveDisplays;
 
  public:
-  static RefPtr<GLLibraryEGL> Create(nsACString* const out_failureId);
+  static RefPtr<GLLibraryEGL> Get(nsACString* const out_failureId);
+  static void Shutdown();
 
  private:
   ~GLLibraryEGL() = default;
 
+  static StaticMutex sMutex;
+  static StaticRefPtr<GLLibraryEGL> sInstance GUARDED_BY(sMutex);
+
   bool Init(nsACString* const out_failureId);
   void InitLibExtensions();
 
+  std::shared_ptr<EglDisplay> CreateDisplayLocked(
+      bool forceAccel, nsACString* const out_failureId,
+      const StaticMutexAutoLock& aProofOfLock);
+
  public:
   Maybe<SymbolLoader> GetSymbolLoader() const;
 
@@ -599,8 +609,9 @@ class EglDisplay final {
   struct PrivateUseOnly final {};
 
  public:
-  static std::shared_ptr<EglDisplay> Create(GLLibraryEGL&, EGLDisplay,
-                                            bool isWarp);
+  static std::shared_ptr<EglDisplay> Create(
+      GLLibraryEGL&, EGLDisplay, bool isWarp,
+      const StaticMutexAutoLock& aProofOfLock);
 
   // Only `public` for make_shared.
   EglDisplay(const PrivateUseOnly&, GLLibraryEGL&, EGLDisplay, bool isWarp);
diff -up firefox-99.0/gfx/webrender_bindings/RenderThread.cpp.D142257 firefox-99.0/gfx/webrender_bindings/RenderThread.cpp
--- firefox-99.0/gfx/webrender_bindings/RenderThread.cpp.D142257	2022-03-31 01:24:51.000000000 +0200
+++ firefox-99.0/gfx/webrender_bindings/RenderThread.cpp	2022-04-06 10:32:53.288145587 +0200
@@ -1163,7 +1163,7 @@ static already_AddRefed<gl::GLContext> C
   }
 
   nsCString failureId;
-  const auto lib = gl::DefaultEglLibrary(&failureId);
+  const auto lib = gl::GLLibraryEGL::Get(&failureId);
   if (!lib) {
     aError.Assign(
         nsPrintfCString("RcANGLE(load EGL lib failed: %s)", failureId.get()));