--- a/widget/nsBaseWidget.cpp
+++ b/widget/nsBaseWidget.cpp
@@ -1279,17 +1279,17 @@ already_AddRefed<CompositorVsyncDispatch
 nsBaseWidget::GetCompositorVsyncDispatcher() {
   MOZ_ASSERT(mCompositorVsyncDispatcherLock.get());
 
   MutexAutoLock lock(*mCompositorVsyncDispatcherLock.get());
   RefPtr<CompositorVsyncDispatcher> dispatcher = mCompositorVsyncDispatcher;
   return dispatcher.forget();
 }
 
-already_AddRefed<LayerManager> nsBaseWidget::CreateCompositorSession(
+already_AddRefed<WebRenderLayerManager> nsBaseWidget::CreateCompositorSession(
     int aWidth, int aHeight, CompositorOptions* aOptionsOut) {
   MOZ_ASSERT(aOptionsOut);
 
   do {
     CreateCompositorVsyncDispatcher();
 
     gfx::GPUProcessManager* gpu = gfx::GPUProcessManager::Get();
     // Make sure GPU process is ready for use.
@@ -1334,30 +1334,29 @@ already_AddRefed<LayerManager> nsBaseWid
 #ifdef MOZ_WIDGET_ANDROID
     if (!GetNativeData(NS_JAVA_SURFACE)) {
       options.SetInitiallyPaused(true);
     }
 #else
     options.SetInitiallyPaused(CompositorInitiallyPaused());
 #endif
 
-    RefPtr<LayerManager> lm = new WebRenderLayerManager(this);
+    RefPtr<WebRenderLayerManager> lm = new WebRenderLayerManager(this);
 
     bool retry = false;
     mCompositorSession = gpu->CreateTopLevelCompositor(
         this, lm, GetDefaultScale(), options, UseExternalCompositingSurface(),
         gfx::IntSize(aWidth, aHeight), &retry);
 
     if (mCompositorSession) {
       TextureFactoryIdentifier textureFactoryIdentifier;
       nsCString error;
-      lm->AsWebRenderLayerManager()->Initialize(
-          mCompositorSession->GetCompositorBridgeChild(),
-          wr::AsPipelineId(mCompositorSession->RootLayerTreeId()),
-          &textureFactoryIdentifier, error);
+      lm->Initialize(mCompositorSession->GetCompositorBridgeChild(),
+                     wr::AsPipelineId(mCompositorSession->RootLayerTreeId()),
+                     &textureFactoryIdentifier, error);
       if (textureFactoryIdentifier.mParentBackend != LayersBackend::LAYERS_WR) {
         retry = true;
         DestroyCompositor();
         // gfxVars::UseDoubleBufferingWithCompositor() is also disabled.
         gfx::GPUProcessManager::Get()->DisableWebRender(
             wr::WebRenderError::INITIALIZE, error);
       }
     }
@@ -1391,17 +1390,18 @@ void nsBaseWidget::CreateCompositor(int 
 
   // If we've already received a shutdown notification, don't try
   // create a new compositor.
   if (!mShutdownObserver) {
     return;
   }
 
   CompositorOptions options;
-  RefPtr<LayerManager> lm = CreateCompositorSession(aWidth, aHeight, &options);
+  RefPtr<WebRenderLayerManager> lm =
+      CreateCompositorSession(aWidth, aHeight, &options);
   if (!lm) {
     return;
   }
 
   MOZ_ASSERT(mCompositorSession);
   mCompositorBridgeChild = mCompositorSession->GetCompositorBridgeChild();
   SetCompositorWidgetDelegate(
       mCompositorSession->GetCompositorWidgetDelegate());
@@ -1415,24 +1415,22 @@ void nsBaseWidget::CreateCompositor(int 
 
   if (mInitialZoomConstraints) {
     UpdateZoomConstraints(mInitialZoomConstraints->mPresShellID,
                           mInitialZoomConstraints->mViewID,
                           Some(mInitialZoomConstraints->mConstraints));
     mInitialZoomConstraints.reset();
   }
 
-  if (lm->AsWebRenderLayerManager()) {
-    TextureFactoryIdentifier textureFactoryIdentifier =
-        lm->GetTextureFactoryIdentifier();
-    MOZ_ASSERT(textureFactoryIdentifier.mParentBackend ==
-               LayersBackend::LAYERS_WR);
-    ImageBridgeChild::IdentifyCompositorTextureHost(textureFactoryIdentifier);
-    gfx::VRManagerChild::IdentifyTextureHost(textureFactoryIdentifier);
-  }
+  TextureFactoryIdentifier textureFactoryIdentifier =
+      lm->GetTextureFactoryIdentifier();
+  MOZ_ASSERT(textureFactoryIdentifier.mParentBackend ==
+             LayersBackend::LAYERS_WR);
+  ImageBridgeChild::IdentifyCompositorTextureHost(textureFactoryIdentifier);
+  gfx::VRManagerChild::IdentifyTextureHost(textureFactoryIdentifier);
 
   WindowUsesOMTC();
 
   mWindowRenderer = std::move(lm);
 
   // Only track compositors for top-level windows, since other window types
   // may use the basic compositor.  Except on the OS X - see bug 1306383
 #if defined(XP_MACOSX)