Bug 1911237 - Disable SurfaceDescriptorD3D10 fast path of CanvasRenderingContext2D::DrawImage() with remote Canvas2d r=gfx-reviewers,lsalzman

STR of Bug 1911237 caused different flickering on different GPUs.  It is better to disable the SurfaceDescriptorD3D10  video rendering optimization of CanvasRenderingContext2D::DrawImage() for now. Though it causes huge performance regression.

Differential Revision: https://phabricator.services.mozilla.com/D218631

dom/canvas/CanvasRenderingContext2D.cpp

@@ -5459,7 +5459,8 @@ MaybeGetSurfaceDescriptorForRemoteCanvas(
       return sd;
     }
     if (subdescType ==
-        layers::RemoteDecoderVideoSubDescriptor::TSurfaceDescriptorD3D10) {
+            layers::RemoteDecoderVideoSubDescriptor::TSurfaceDescriptorD3D10 &&
+        StaticPrefs::gfx_canvas_remote_use_draw_image_fast_path_d3d()) {
       auto& descD3D10 = subdesc.get_SurfaceDescriptorD3D10();
       if (descD3D10.gpuProcessQueryId().isSome() &&
           descD3D10.gpuProcessQueryId().ref().mOnlyForOverlay) {

modules/libpref/init/StaticPrefList.yaml

@@ -5971,6 +5971,11 @@
   value: true
   mirror: always
 
+- name: gfx.canvas.remote.use-draw-image-fast-path-d3d
+  type: RelaxedAtomicBool
+  value: false
+  mirror: always
+
 - name: gfx.canvas.remote.recycle-used-data-surface
   type: RelaxedAtomicBool
   value: true