Make SkComposeImageFilter comply with SkImageFilter::filterBounds calling convention

In kForward mode the 'inputRect' parameter is supposed to be null

Bug: 959103
Change-Id: I2fceace384cdda3988e07dcb5d975750ba28bd39
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/212187
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
1 file changed