diff --git a/gfx/thebes/gfxPlatform.cpp b/gfx/thebes/gfxPlatform.cpp
index 1d34267a409b..a6a7a43030f9 100644
--- a/gfx/thebes/gfxPlatform.cpp
+++ b/gfx/thebes/gfxPlatform.cpp
@@ -3099,24 +3099,6 @@ bool gfxPlatform::PerfWarnings() {
   return StaticPrefs::gfx_perf_warnings_enabled();
 }
 
-void gfxPlatform::GetAcceleratedCompositorBackends(
-    nsTArray<LayersBackend>& aBackends) {
-  if (gfxConfig::IsEnabled(Feature::OPENGL_COMPOSITING)) {
-    aBackends.AppendElement(LayersBackend::LAYERS_OPENGL);
-  } else {
-    static int tell_me_once = 0;
-    if (!tell_me_once) {
-      NS_WARNING("OpenGL-accelerated layers are not supported on this system");
-      tell_me_once = 1;
-    }
-#ifdef MOZ_WIDGET_ANDROID
-    MOZ_CRASH(
-        "OpenGL-accelerated layers are a hard requirement on this platform. "
-        "Cannot continue without support for them");
-#endif
-  }
-}
-
 void gfxPlatform::NotifyCompositorCreated(LayersBackend aBackend) {
   if (mCompositorBackend == aBackend) {
     return;
diff --git a/gfx/thebes/gfxPlatform.h b/gfx/thebes/gfxPlatform.h
index 5d7d013afeca..924aacaa98b6 100644
--- a/gfx/thebes/gfxPlatform.h
+++ b/gfx/thebes/gfxPlatform.h
@@ -834,11 +834,6 @@ class gfxPlatform : public mozilla::layers::MemoryPressureListener {
   // platform.
   virtual bool AccelerateLayersByDefault();
 
-  // Returns a prioritized list of available compositor backends for
-  // acceleration.
-  virtual void GetAcceleratedCompositorBackends(
-      nsTArray<mozilla::layers::LayersBackend>& aBackends);
-
   // Returns preferences of canvas and content backends.
   virtual BackendPrefsData GetBackendPrefs() const;
 
diff --git a/gfx/thebes/gfxWindowsPlatform.cpp b/gfx/thebes/gfxWindowsPlatform.cpp
index b7f56b9b288a..a9cefe10d5e9 100644
--- a/gfx/thebes/gfxWindowsPlatform.cpp
+++ b/gfx/thebes/gfxWindowsPlatform.cpp
@@ -1756,18 +1756,6 @@ gfxWindowsPlatform::CreateHardwareVsyncSource() {
   return d3dVsyncSource.forget();
 }
 
-void gfxWindowsPlatform::GetAcceleratedCompositorBackends(
-    nsTArray<LayersBackend>& aBackends) {
-  if (gfxConfig::IsEnabled(Feature::OPENGL_COMPOSITING) &&
-      StaticPrefs::layers_prefer_opengl_AtStartup()) {
-    aBackends.AppendElement(LayersBackend::LAYERS_OPENGL);
-  }
-
-  if (gfxConfig::IsEnabled(Feature::D3D11_COMPOSITING)) {
-    aBackends.AppendElement(LayersBackend::LAYERS_D3D11);
-  }
-}
-
 void gfxWindowsPlatform::ImportGPUDeviceData(
     const mozilla::gfx::GPUDeviceData& aData) {
   MOZ_ASSERT(XRE_IsParentProcess());
diff --git a/gfx/thebes/gfxWindowsPlatform.h b/gfx/thebes/gfxWindowsPlatform.h
index 9bb06dd750fb..a439d2303d35 100644
--- a/gfx/thebes/gfxWindowsPlatform.h
+++ b/gfx/thebes/gfxWindowsPlatform.h
@@ -204,8 +204,6 @@ class gfxWindowsPlatform final : public gfxPlatform {
 
  protected:
   bool AccelerateLayersByDefault() override { return true; }
-  void GetAcceleratedCompositorBackends(
-      nsTArray<mozilla::layers::LayersBackend>& aBackends) override;
   nsTArray<uint8_t> GetPlatformCMSOutputProfileData() override;
   void GetPlatformDisplayInfo(mozilla::widget::InfoObject& aObj) override;