Bug 1728903 - Remove plumbing for CanvasLayer and ImageLayer. r=mattwoodrow

Differential Revision: https://phabricator.services.mozilla.com/D124406

dom/html/HTMLCanvasElement.h

@@ -31,7 +31,6 @@ class ClientWebGLContext;
 
 namespace layers {
 class CanvasRenderer;
-class CanvasLayer;
 class Image;
 class Layer;
 class LayerManager;
@@ -122,7 +121,6 @@ class HTMLCanvasElement final : public nsGenericHTMLElement,
   enum { DEFAULT_CANVAS_WIDTH = 300, DEFAULT_CANVAS_HEIGHT = 150 };
 
   typedef layers::CanvasRenderer CanvasRenderer;
-  typedef layers::CanvasLayer CanvasLayer;
   typedef layers::Layer Layer;
   typedef layers::LayerManager LayerManager;
   typedef layers::WebRenderCanvasData WebRenderCanvasData;
@@ -298,18 +296,11 @@ class HTMLCanvasElement final : public nsGenericHTMLElement,
    * Helpers called by various users of Canvas
    */
 
-  already_AddRefed<Layer> GetCanvasLayer(nsDisplayListBuilder* aBuilder,
-                                         Layer* aOldLayer,
-                                         LayerManager* aManager);
   already_AddRefed<layers::Image> GetAsImage();
   bool UpdateWebRenderCanvasData(nsDisplayListBuilder* aBuilder,
                                  WebRenderCanvasData* aCanvasData);
   bool InitializeCanvasRenderer(nsDisplayListBuilder* aBuilder,
                                 CanvasRenderer* aRenderer);
-  // Should return true if the canvas layer should always be marked inactive.
-  // We should return true here if we can't do accelerated compositing with
-  // a non-BasicCanvasLayer.
-  bool ShouldForceInactiveLayer(LayerManager* aManager);
 
   // Call this whenever we need future changes to the canvas
   // to trigger fresh invalidation requests. This needs to be called