script: A couple mutation observer fixes.
I felt like doing Servo stuff while trying to catch Gecko intermittents :)
This fixes most of #21233. I haven't dug into the other test.
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Implement update source set & select image source
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Make fetch() API use same-origin credentials by default
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Allow supported window attributes to be replacable.
As seen in https://github.com/servo/servo/pull/21045 some Window attributes don't support JavaScript from being able to shadow and replace their values.
This PR adds all other attributes I could find that are supported by servo to be replaceable.
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textarea minLength/maxLength
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textarea minLength/maxLength
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Let the popstate and hashchange events not bubble
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fix#21063
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add TextLength
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add TextLength in HTMLTextAreaElement
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Implement window.length DOM attribute.
Implements the `window.length` DOM attribute for enumerating frames on the document.
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Allow window.parent attribute to be replaceable by JavaScript.
Permit JS to override the window.parent attribute.
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Update WPT upstream sync metadata.
This is the result of running `./mach update-wpt --upstream` with appropriate credentials.
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Respect the source rectangle when drawing a canvas to another canvas.
This allows us to run the three.js examples without panicking, since they use self-drawing canvases to scroll the FPS graph.
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