Sort GM/sample slides in Viewer.
Sort GM/sample slides in Viewer.

Previously, GMs were displayed in a chaotic somewhat-alphabetical order,
and samples were displayed in a reverse somewhat-alphabetical order. Now
we actually sort them by name.

Additionally, switched to sk_make_sp to make sk_sp (in the spirit of
go/totw/126).

Change-Id: I94abd52d6f0ba65b6e23108f9f6aeed1c7ddf08f
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/481678
Reviewed-by: Ben Wagner <53965154ffeecc4a10886eab9259e95965f2979a@google.com>
Commit-Queue: John Stiles <f4fcf42d3bb5924557f1eeb3be66747535e585da@google.com>
Auto-Submit: John Stiles <f4fcf42d3bb5924557f1eeb3be66747535e585da@google.com>

google/skia,aosp-mirror/platform_external_skia,google/skia,google/skia,google/skia,aosp-mirror/platform_external_skia,google/skia,google/skia,aosp-mirror/platform_external_skia,google/skia,aosp-mirror/platform_external_skia,google/skia,aosp-mirror/platform_external_skia,google/skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,google/skia,aosp-mirror/platform_external_skia