WebNN: Support AllowSharedBufferSource for constant
This CL implements the WebNN spec change proposal 1 that uses
AllowSharedBufferSource for MLGraphBuilder.constant().
Bug: 380896836
Change-Id: Ib8fc58daaabf7493b08f9634daa1eeb08a50ad35
Cq-Include-Trybots: luci.chromium.try:win11-blink-rel, mac14.arm64-blink-rel, mac15.arm64-blink-rel, linux-blink-rel
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6050722
Reviewed-by: Austin Sullivan asully@chromium.org
Reviewed-by: Weizhong Xia weizhong@google.com
Commit-Queue: ningxin hu ningxin.hu@intel.com
Cr-Commit-Position: refs/heads/main@{#1390750}