Don't update iframe pipeline until load completes
To preserve the previous functionality of delaying load events when a
new navigation is triggered, pending pipeline id represents the
current pending load. The load event is only fired if the load message's
pipeline id matches the pending pipeline id.
Track frame size on Frame instead of Pipeline
Disabled matchMedia test
Track creator pipeline id
Rename ScriptChan in constellation to EventLoop
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We currently have a type `ScriptChan` in the constellation, which is named after its implementation rather than its semantics. In the spec, the nearest concept seems to be event loop https://html.spec.whatwg.org/multipage/#event-loop.
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Script lookup iframes by frameid
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Lookup iframes by `FrameId` rather than `PipelineId`. This should make lookup much more reliable, since the frame id doesn't change.
cc @ConnorGBrewster @aneeshusa
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- [X] These changes do not require tests because refactoring
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