onnxruntime

78cf3eb5 - Fix WebGPU context memory identity and test host-owned caches (#33110)

Fix WebGPU context memory identity and test host-owned caches (#33110) ## Summary Native external-Dawn hosts can supply a Dawn instance and device with a positive ORT context ID. WebGPU allocators previously advertised memory-device ID zero regardless of that context, leaving allocator lookup, streams, and transfer routing unable to distinguish separate Dawn memory domains. Plugin stream validation exposed this mismatch during custom-context session initialization. This PR fixes the identity mismatch rather than weakening the stream check: - Propagate the context ID through WebGPU session allocators and the plugin's default memory device, with range validation before context creation. - Forward the requested memory device to plugin stream creation and retain the owning-context identity check. - Route shared WebGPU transfers using tensor memory-device IDs and reject GPU copies between distinct contexts or foreign GPU vendors. - Extend the native external-host test with host-created devices, synchronized cache callbacks, cache isolation keys, lifetime checks, and failure cases. - Keep default and host-owned sessions alive together; verify distinct allocator and GPU-output IDs, CPU/GPU and same-context GPU/GPU transfers, and rejection of cross-context copies. - Exercise the native host through existing Windows source-based, package-backed built-in, and plugin CI paths, and document device/callback ownership. Our current deployment uses built-in WebGPU with external Dawn and a host-owned device. Plugin and concurrent-context tests are additional regression coverage, not a claim that the deployment has migrated to plugins or requires a default session alongside the host-owned session. Context IDs identify Dawn memory domains, not physical GPU indices. No new public API is introduced. ## Validation Windows x64 Release with native Dawn: - Refreshed source-based built-in, package-backed built-in, and package-backed plugin builds passed all five host modes, with CPU fallback disabled. - All three exercised default/custom context allocation and GPU-bound outputs, same-context transfers, and cross-context rejection. - All three observed three actual warm-cache hits and no additional hits under a different isolation key, and verified host-device use after ORT teardown. - Required-feature rejection, callback failure containment, and missing-proc-table rejection passed with their expected diagnostics. - All 35 plugin framework tests passed, including the requested stream-device forwarding regression. - All four WebGPU transfer tests and the device-ID parser rejection test passed. - All 15 changed C++ files passed scoped ORT lintrunner formatting checks. Other native platforms remain unvalidated locally. Cache reuse is tested across devices within one process; persistence across process restarts is not covered.