Make SMILAnimationSandwich devour more functionality

Functionality from SMILTimeContainer has been moved into
SMILAnimationSandwich. The HashMap with animations has been
changed to contain SMILAnimationSandwich:s which manage themselves
instead of SMILTimeContainer sorting it out (pun intended).

The PriorityCompare struct has been moved into SMILAnimationSandwich,
so both SMILAnimationSandwich and SMILTimeContainer can sort things.

Bug: 981522
Change-Id: I2ab4b09b11c0a6c2f0ad74af08e661abd5afa84a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1704099
Commit-Queue: Fredrik Söderquist <fs@opera.com>
Reviewed-by: Fredrik Söderquist <fs@opera.com>
Auto-Submit: Edvard Thörnros <edvardt@opera.com>
Cr-Commit-Position: refs/heads/master@{#678180}
4 files changed