Finish the JSON clone algorithm for WebDriver
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This makes some tests regarding clearing rects pass. Otherwise the rect
wouldn't get cleared properly and it'd keep its original color but get
an alpha of 0
I tried to mimic the azure implementation but raqote doesn't have a
concept of horizontal or vertical repeat so this might be
wrong/incomplete but this is the last function needed to finally have
some tests pass
Use ipc router in webdriver
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Fix for https://github.com/servo/servo/issues/23905#issuecomment-522588119
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Support default toJSON in WebIDL
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Ported related lines from gecko.
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Implement TakeElementScreenshot WebDriver command
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Update servo-media. Remove implicit shutdown requests. It all happens…
… automagicly now
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Return ErrorStatus from webdriver_handlers
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With `webdriver 0.40`, `ErrorStatus` implements `Deserialize`. Now we can accommodate for multiple errors occuring in `webdriver_handlers`.
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