c85641800591028c9a9e231f54e0146e1b55d97a  [Image Redux] Add overloads in ImageAdapter that take a concrete object size and image extras

Classified as not security-relevant.
Triage note: Threads ConcreteObjectSize and ImageDrawingExtras through ImageAdapter (nsImage/tiffRepresentation/getHBITMAP/snapshotNSImage) and adds a RasterizationKey so the cached NSImage/TIFF is re-rendered when size/extras change. Plumbing plus a cache-key correctness improvement; no security bug.
This commit was flagged by the signal scorer and reviewed by AI (not a human). It is listed only so the triage is auditable; there is no root-cause analysis because this is not a vulnerability fix.

Structural signals: smartptr_member_added (+6.47)