Alternate between two SkBitmaps in SkAnimatedImage

Bug: 78866720

The client in Android calls newPictureSnapshot, which results in copying
the mutable SkBitmap into a newly allocated one in each frame. Avoid
this by calling SkMakeImageFromRasterBitmap with
kNever_SkCopyPixelsMode. Make SkAnimatedImage copy on write, by copying
before decoding if the bitmap's pixel ref is not unique.

Android's AnimatedImageDrawable's current architecture only decodes one
frame in advance, so it will never need to perform the copy on write.
This will save one bitmap allocation per GIF frame.

Add a test to verify that copy on write works as expected.

Change-Id: I87eb6e84089096cd2d618b91fb627fc58677e66a
Reviewed-on: https://skia-review.googlesource.com/129841
Reviewed-by: Leon Scroggins <scroggo@google.com>
Commit-Queue: Leon Scroggins <scroggo@google.com>
Auto-Submit: Leon Scroggins <scroggo@google.com>

0 files changed, 0 insertions, 0 deletions