The GalleryActivity and GalleryFragment make unusual assumptions around Activity and Fragment behaviors. As they're medium sized legacy classes, they should be considered candidates to be remade with conventional app considerations. This spike encompasses the following work:

• Create GalleryOverhaulActivity and Fragment shells per app conventions
• Over the course of several small and pointed patches, start copying clean code into them
• Identify work that would be necessary to finish the job. Specifically, at a class level or lower, anything that would need a rework
• If it's worth continuing, commit at least the shells and hopefully a little clean code to the repo and create new cards for all remaining work identified. A card for design considerations should also be considered (for example, T109237)