canvas: Add OffscreenCanvas 'transferToImageBitmap' method (#37880)

Follow the HTML speficication and add missing 'transferToImageBitmap'
method to OffscreenCanvas interface.

https://html.spec.whatwg.org/multipage/#dom-offscreencanvas-transfertoimagebitmap

Testing: Improvements in the following tests
- html/canvas/offscreen/compositing/2d.composite.grid*
- html/canvas/offscreen/fill-and-stroke-styles/2d.gradient*
- html/canvas/offscreen/manual/the-offscreen-canvas/offscreencanvas*
- html/canvas/offscreen/reset/2d.reset*
- html/canvas/offscreen/text/2d.text*

Fixes (partially): #34111

Signed-off-by: Andrei Volykhin <andrei.volykhin@gmail.com>

components/script/dom/webgpu/gpucanvascontext.rs

@@ -276,6 +276,10 @@ impl CanvasContext for GPUCanvasContext {
         }
     }
 
+    fn reset_bitmap(&self) {
+        warn!("The GPUCanvasContext 'reset_bitmap' is not implemented yet");
+    }
+
     /// <https://gpuweb.github.io/gpuweb/#ref-for-abstract-opdef-get-a-copy-of-the-image-contents-of-a-context%E2%91%A5>
     fn get_image_data(&self) -> Option<Snapshot> {
         // 1. Return a copy of the image contents of context.