BREAKING(web-sys): Remove support for CanvasRenderingContext2D and BufferSource from createImageBitmap (#3231)

Resolves #3227

Both APIs are broken, to some extent, which is why I think it makes sense to remove them despite the potential breakage. Calling `createImageBitmap` with a `BufferSource` will instantly throw an error, and calling it with a `CanvasRenderingContext2D` will also fail except in Firefox, where it gives a deprecation warning.

`BufferSource` was there as part of the abandoned video capture worker API (https://w3c.github.io/mediacapture-worker). It looks like we inherited it from Firefox, which supported it behind a flag at the time we copied our WebIDL from it but later removed it. I also removed the rest of that API while I was at it.

`CanvasRenderingContext2D` is there because, for whatever reason, Firefox non-standardly accepts it in `createImageBitmap`, and we took our WebIDL from them. It's deprecated, and https://bugzilla.mozilla.org/show_bug.cgi?id=1500782 talks about removing it, but it hasn't been done yet.

Author: Liamolucko

crates/web-sys/src/features/gen_ChannelPixelLayout.rs

@@ -32,60 +32,4 @@ extern "C" {
     #[doc = ""]
     #[doc = "*This API requires the following crate features to be activated: `ImageBitmap`*"]
     pub fn close(this: &ImageBitmap);
-    #[cfg(feature = "ImageBitmapFormat")]
-    # [wasm_bindgen (catch , method , structural , js_class = "ImageBitmap" , js_name = findOptimalFormat)]
-    #[doc = "The `findOptimalFormat()` method."]
-    #[doc = ""]
-    #[doc = "[MDN Documentation](https://developer.mozilla.org/en-US/docs/Web/API/ImageBitmap/findOptimalFormat)"]
-    #[doc = ""]
-    #[doc = "*This API requires the following crate features to be activated: `ImageBitmap`, `ImageBitmapFormat`*"]
-    pub fn find_optimal_format(this: &ImageBitmap) -> Result<ImageBitmapFormat, JsValue>;
-    #[cfg(feature = "ImageBitmapFormat")]
-    # [wasm_bindgen (catch , method , structural , js_class = "ImageBitmap" , js_name = findOptimalFormat)]
-    #[doc = "The `findOptimalFormat()` method."]
-    #[doc = ""]
-    #[doc = "[MDN Documentation](https://developer.mozilla.org/en-US/docs/Web/API/ImageBitmap/findOptimalFormat)"]
-    #[doc = ""]
-    #[doc = "*This API requires the following crate features to be activated: `ImageBitmap`, `ImageBitmapFormat`*"]
-    pub fn find_optimal_format_with_a_possible_formats(
-        this: &ImageBitmap,
-        a_possible_formats: &::wasm_bindgen::JsValue,
-    ) -> Result<ImageBitmapFormat, JsValue>;
-    #[cfg(feature = "ImageBitmapFormat")]
-    # [wasm_bindgen (catch , method , structural , js_class = "ImageBitmap" , js_name = mapDataInto)]
-    #[doc = "The `mapDataInto()` method."]
-    #[doc = ""]
-    #[doc = "[MDN Documentation](https://developer.mozilla.org/en-US/docs/Web/API/ImageBitmap/mapDataInto)"]
-    #[doc = ""]
-    #[doc = "*This API requires the following crate features to be activated: `ImageBitmap`, `ImageBitmapFormat`*"]
-    pub fn map_data_into_with_buffer_source(
-        this: &ImageBitmap,
-        a_format: ImageBitmapFormat,
-        a_buffer: &::js_sys::Object,
-        a_offset: i32,
-    ) -> Result<::js_sys::Promise, JsValue>;
-    #[cfg(feature = "ImageBitmapFormat")]
-    # [wasm_bindgen (catch , method , structural , js_class = "ImageBitmap" , js_name = mapDataInto)]
-    #[doc = "The `mapDataInto()` method."]
-    #[doc = ""]
-    #[doc = "[MDN Documentation](https://developer.mozilla.org/en-US/docs/Web/API/ImageBitmap/mapDataInto)"]
-    #[doc = ""]
-    #[doc = "*This API requires the following crate features to be activated: `ImageBitmap`, `ImageBitmapFormat`*"]
-    pub fn map_data_into_with_u8_array(
-        this: &ImageBitmap,
-        a_format: ImageBitmapFormat,
-        a_buffer: &mut [u8],
-        a_offset: i32,
-    ) -> Result<::js_sys::Promise, JsValue>;
-    #[cfg(feature = "ImageBitmapFormat")]
-    # [wasm_bindgen (catch , method , structural , js_class = "ImageBitmap" , js_name = mappedDataLength)]
-    #[doc = "The `mappedDataLength()` method."]
-    #[doc = ""]
-    #[doc = "[MDN Documentation](https://developer.mozilla.org/en-US/docs/Web/API/ImageBitmap/mappedDataLength)"]
-    #[doc = ""]
-    #[doc = "*This API requires the following crate features to be activated: `ImageBitmap`, `ImageBitmapFormat`*"]
-    pub fn mapped_data_length(
-        this: &ImageBitmap,
-        a_format: ImageBitmapFormat,
-    ) -> Result<i32, JsValue>;
 }