Bug 1885447 - Tonemap/color-manage webgl sdr/wcg output into Display profile as pre-compositor post-process. r=gfx-reviewers,webidl,smaug,ahale

Differential Revision: https://phabricator.services.mozilla.com/D207651

dom/canvas/ClientWebGLContext.h

@@ -1052,6 +1052,20 @@ class ClientWebGLContext final : public nsICanvasRenderingContextInternal,
     const FuncScope funcScope(*this, "drawingBufferHeight");
     return AutoAssertCast(DrawingBufferSize().y);
   }
+
+  // -
+
+ private:
+  dom::PredefinedColorSpace mDrawingBufferColorSpace =
+      dom::PredefinedColorSpace::Srgb;
+
+ public:
+  auto DrawingBufferColorSpace() const { return mDrawingBufferColorSpace; }
+
+  void SetDrawingBufferColorSpace(dom::PredefinedColorSpace);
+
+  // -
+
   void GetContextAttributes(dom::Nullable<dom::WebGLContextAttributes>& retval);
 
  private: