[Mustapha Jaber (mustjab)]

Summary

The common WebGPU context handles both bundled and host-provided Dawn, but it also includes Dawn native/platform headers and implements the bundled worker pool. Move the implementation-dependent code into a bundled-only translation unit so that the common context no longer depends on dawn::native or dawn::platform.

• Extract default proc-table lookup, custom-platform instance creation, and native adapter enumeration behind private typed helpers.
• Exclude the bundled-only source from external-Dawn and Emscripten builds.
• Preserve worker-pool sizing, platform lifetime, instance features, and adapter-selection behavior. No public API or packaging changes.

Validation

• Windows x64 Release, bundled Dawn: built onnxruntime_provider_test; ran WebGpuContextTest.*, with 27 passed and one expected skip (AdapterIndexRejectsUnsupportedBuild). This includes physical adapter selection and device operations.
• Windows x64 Release, --use_webgpu --use_external_dawn: configured and built onnxruntime_providers_webgpu. The bundled-only translation unit is excluded from the generated project.
• Scoped lintrunner and git diff --cached --check passed.

External-host runtime and Emscripten execution were not tested locally.

[Copilot]

Copilot review overview

🟢 Approval recommended

The implementation preserves behavior and build isolation; only minor missing license headers remain.

Review effort: Balanced
Findings: 2

Open (2)

• Add copyright and MIT license header to source file · New
• Add copyright and MIT license header to header file · New

What changed in this PR

Isolates bundled Dawn dependencies from the common WebGPU context while preserving existing behavior.

Changes:

• Moves native Dawn platform, proc-table, instance, and adapter logic into dedicated helpers.
• Excludes bundled-only implementation from external-Dawn and Emscripten builds.
• Updates context creation and adapter enumeration to use the helpers.

File	Description
webgpu_context.cc	Uses bundled-Dawn helper APIs.
webgpu_context_dawn_platform.h	Declares internal helper APIs.
webgpu_context_dawn_platform.cc	Implements bundled Dawn integration.
onnxruntime_providers_webgpu.cmake	Excludes bundled implementation where unsupported.

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