Apply auto expiry mechanism to GPUExternalTexture

WebGPU spec updated GPUExternalTexture expire mechanism. It removes
GPUExternalTexture.expire and uses auto expiry mechanism.

The basic rules are:
- ImportExternalTexture should return same object if underly
  resource is the same.
- GPUExternalTexture should be expire if current task scope finished.
  And could be refreshed by importExternalTexture in new task scope.

This CL adds auto expiry mechanism and a cache to address these requirements.

Bug: chromium:1412338
Change-Id: I6ca72d2ea9a013d7729072cb76cb412ecf3a1e86
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4258147
Commit-Queue: Shaobo Yan <shaobo.yan@intel.com>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1112071}