canvas2d: Disable shared images completely for low latency canvas.

Ensure that we never use shared images for low latency canvas until it
can support single buffering.

R=fserb@chromium.org

Bug: 976774
Change-Id: I093b3627f05233ea4f7212eb3093c805498bf2ea
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1669918
Auto-Submit: Khushal <khushalsagar@chromium.org>
Commit-Queue: Fernando Serboncini <fserb@chromium.org>
Reviewed-by: Fernando Serboncini <fserb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#671440}

third_party/blink/renderer/platform/graphics/canvas_resource_provider.cc

@@ -920,6 +920,12 @@ std::unique_ptr<CanvasResourceProvider> CanvasResourceProvider::Create(
             size, color_params, context_provider_wrapper, resource_dispatcher);
         break;
       case CanvasResourceType::kSharedImage: {
+        if (usage == kAcceleratedDirect2DResourceUsage ||
+            usage == kAcceleratedDirect3DResourceUsage) {
+          // Shared images don't work for single buffered canvas yet.
+          continue;
+        }
+
         // TODO(khushalsagar): Also kAcceleratedDirect2DResourceUsage when we
         // switch it to use shared images.
         const bool is_overlay_candidate =