Add the reflected 'sizes' IDL attribute for <image> element's DOM
interface which defines image sizes for different page layouts.
See https://html.spec.whatwg.org/multipage/#dom-img-sizes
Testing: Improvements in the following tests
- custom-elements/reactions/customized-builtins/HTMLImageElement.html
- html/dom/idlharness.https.html
-
html/semantics/embedded-content/the-img-element/relevant-mutations.html
Signed-off-by: Andrei Volykhin <andrei.volykhin@gmail.com>
Follow the HTML specification and take into account that the HTML
`<image>/<source>` element inserting/removal steps should only be
counted as relevant mutations for `<image>` element if the parent of the
inclusive ancestor that was inserted/removed is the parent `<picture>`
element.
See <https://html.spec.whatwg.org/multipage/#relevant-mutations>.
Testing: Improvements in the following tests
-
html/semantics/embedded-content/the-img-element/relevant-mutations.html
Signed-off-by: Andrei Volykhin <andrei.volykhin@gmail.com>