flutter/engine#51229 blocked [the roll](#146522) and had to be reverted, which is a shame, but on the bright side it made it possible to point the framework at my removal pr, at the point of its merging the first time 

This fixes all errors that are fixable in the framework that would have blocked the roll. There are some that aren't fixable here (they need to be fixed in the engine)*, so I'll fix those in the engine but unfortunately I can't pick up another version here to re-test until I try to roll again � 

*This category is: uses of plugins that in turn have a `registerWith`, that references the v1 embedding. The plan to fix these cases is to leave the interface that that method relies on around for now. See flutter/packages#6494 (comment) for details

…146523)

flutter/engine#51229 blocked [the roll](flutter#146522) and had to be reverted, which is a shame, but on the bright side it made it possible to point the framework at my removal pr, at the point of its merging the first time 

This fixes all errors that are fixable in the framework that would have blocked the roll. There are some that aren't fixable here (they need to be fixed in the engine)*, so I'll fix those in the engine but unfortunately I can't pick up another version here to re-test until I try to roll again � 

*This category is: uses of plugins that in turn have a `registerWith`, that references the v1 embedding. The plan to fix these cases is to leave the interface that that method relies on around for now. See flutter/packages#6494 (comment) for details