* Take two: Delay reading image back from render backend using `SyncHandle`
This allows us to avoid blocking immediately after a `BitmapData.draw` call.
Instead, we only attempt to use the `SyncHandle` when performing an operation
that requires the CPU-side pixels (e.g. BitmapData.getPixel or BitmapData.setPixel).
In the best case, the SWF will never explicitly access the pixels of
the target BitmapData, removing the need to ever copy back the render backend
image to our BitmapData. If the SWF doesn't require access to the pixels immediately,
we can delay copying the pixels until they're actually needed, hopefully allowing
the render backend to finish processing the BitmapData.draw operation in
the backenground before we need the result.
Now that the CPU and GPU pixels can be intentionally out of sync with
each other, we need to ensure that we don't accidentally expose 'stale'
CPU-side pixels to ActionScript (which needs to remain unaware of
our internal laziness). We now use a wrapper type `BitmapDataWrapper`
to enforce that the `SyncHandle` is consumed before accessing the
underlying `BitmapData.
* core: Skip GPU->CPU sync for source and target BitmapData during draw
* Introduce DirtyState enum
Previously we were removing the first occurrence of the invalid
0xFFD9FFD8 byte sequence in JPEG data, but this would break the
JPEG if it happened to contain this byte sequence elsewhere (for
example, EXIF data). Instead, properly parse the JPEG markers
searching for the invalid marker sequence.
Fixes#8775.
This makes `Bitmap` delegate to `BitmapData` for
all of the bitmap-related information (handle, width, and height).
As a result, we now unconditionally store a `BitmapData` in `Bitmap`.
As a result, swapping the underling `BitmapData` instance will
automatically change the properties (and rendered image) of a `Bitmap`.
This required some refactoring in the render backends in order to
get access to a `BitmapHandle` through `BitmapData`.