Bug 1612440 - Separate scene and frame related data in DocumentView. r=gw

DocumentView has a mix of members that affect scene building and memebers that change frame to frame. These need to be updated at different rates and more importantly follow the respective flow of scene and frame transactions, which wasn't done properly before this change.

Depends on D71781

Differential Revision: https://phabricator.services.mozilla.com/D71927

UltraBlame original commit: 4933e4b66edb70f5b8f682abc6025e9f50f14e4b

Author: marco-c