Add a WebGPU page to porting with a link to a tutorial (#26862)

Co-authored-by: Kai Ninomiya <kainino@chromium.org>

Author: dschuff

site/source/docs/porting/multimedia_and_graphics/WebGPU-support.rst

@@ -0,0 +1,11 @@
+.. _WebGPU-support:
+
+==========================
+Using WebGPU in Emscripten
+==========================
+
+Emscripten supports using WebGPU via `Emdawnwebgpu <https://dawn.googlesource.com/dawn/+/refs/heads/main/src/emdawnwebgpu/pkg/>`_,
+an external Emscripten port that implements a `Dawn <https://dawn.googlesource.com/dawn>`_-like version of the
+`webgpu.h <https://github.com/webgpu-native/webgpu-headers/>`_ C API, on top of the browser's WebGPU.
+See the Emdawnwebgpu link for documentation, and
+`this article <https://developer.chrome.com/docs/web-platform/webgpu/build-app>`_ for an example of how to use it.

site/source/docs/porting/multimedia_and_graphics/index.rst

@@ -10,6 +10,7 @@ This section contains articles about Emscripten's support for graphics and audio
 .. toctree::
    :maxdepth: 1
 
+   WebGPU-support
    EGL-Support-in-Emscripten
    OpenGL-support