onnxruntime

f5812d0e - [WebGPU] Reduce staging buffers for uploading intializers (#23968)

[WebGPU] Reduce staging buffers for uploading intializers (#23968) This change reduces the number of staging buffers used for uploading initializers to the GPU. On the one hand, we early release the upload staging buffers. On the other hand, we use the BufferMapExtendedUsages feature of Dawn on UMA GPUs, which allows us to directly write into the dest GPU buffer without the need of a staging buffer. To achieve this, we need to ensure the UMA GPU buffers are mapped at creation. We have BufferManager to be awared of OnSessionInitializationEnd(), so that it can handle buffer Create() and Upload() calls properly. Credits to @fs-eire for the overall design of implementation.