[Not for review yet] Add CanvasToneMapping to CanvasSettings

[ccameron-chromium]

Copy the GPUToneMapping and GpuToneMappingMode properties from the WebGPU spec to the HTML spec. Add these properties to 2D canvas (now that 2D canvas has float16 support).

After this has landed, the WebGPU spec will need to be updated to point at the new CanvasToneMapping and CanvasToneMappingMode properties in HTML, in the same way that it uses PredefinedColorSpace from HTML.

This has been the planned trajectory of the API since its proposal to WebGPU.

Fixes #11424

• At least two implementers are interested (and none opposed):
  • Chromium: Proposed
  • Gecko: ...
  • WebKit: ...
• Tests are written and can be reviewed and commented upon at:
  • …
• Implementation bugs are filed:
  • Chromium: crbug.com/448552449
  • Gecko: …
  • WebKit: …
• MDN issue is filed: …
• The top of this comment includes a [clear commit message]

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/canvas.html ( diff )