On demand plugins are now per-page, not per-object.

Traverse the frame tree and enable all plugins currently on the page. Remember
the setting for any future plugins that are created. Reset the setting in
makeRepresentation as that seems to be called for all new documents.

Bug: 2564543
Change-Id: I558f068992719ee0236ba40f76b918b10cfe0ed9
3 files changed