`BitmapHandle` now holds `Arc<dyn BitmapHandleImpl>`.
This allows us to move all of the per-bitmap backend data into
`BitmapHandle`, instead of holding an id to a backend-specific
hashmap.
This fixes the memory leak issue with bitmaps. Once the AVM side of a
bitmap (`Bitmap`/`BitmapData`) gets garbage-collected, the
`BitmapHandle` will get dropped, freeing all of the GPU resources
assoicated with the bitmap.
Some recent changes with lyon's API could cause Ruffle to draw extra
strokes when it sees two Move commands in a row -- an extra zero-length
stroke would appear. Let's merge adjacent Move commands in the
tessellator to avoid this issue.
(TODO: Add an example to visual_tests).
lyon would emit a small line segment if a stroke path had
consective MoveTo commands. For the lyon backends, filter out
consecutive MoveTos and only emit the final MoveTo command.
This fixes a small dot appearing in text fields using underlines.
Nathan Adams