WebNN: avoid staging buffers on first inference

Fixes an issue where a staging buffer was always created on first use because its last used fence value was initially set to UINT64_MAX which could never be considered "not in use" until a submission occurred first. Instead, this fence value should of been set the initial value of the queue's fence, which is considered "not in use" without requiring a submission first.

Bug: 358594662
Change-Id: I960d4b55f468f92a8a34bcae896816f2d5e18fc6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5777470


Commit-Queue: ningxin hu <ningxin.hu@intel.com>
Reviewed-by: ningxin hu <ningxin.hu@intel.com>
Reviewed-by: Rafael Cintron <rafael.cintron@microsoft.com>
Cr-Commit-Position: refs/heads/main@{#1339981}

services/webnn/dml/buffer_impl_dml.h

@@ -52,7 +52,7 @@ class BufferImplDml final : public WebNNBufferImpl {
   // The fence value used to track progress of GPU execution of commands using
   // this buffer. Comparing it with the command queue's completed fence can
   // indicate whether commands have completed execution.
-  uint64_t last_submission_fence_value_ = UINT64_MAX;
+  uint64_t last_submission_fence_value_ = 0;
 
   base::WeakPtrFactory<BufferImplDml> weak_factory_{this};
 };