SF: Updating content FPS tracking

1) Each time SF creates a layer, register it with Scheduler and return handle
2) BufferQueueLayer and BufferStateLayer can now send information about buffers
   for given layers via layer handle.

Algorithm for detecting content fps:
1) Keep the refresh rate per layer (explicit timestamp, or 0).
2) Keep information about last 10 present or update timestamps. This will be an
   indicator for precedence.
3) Choose the MAX refresh rate among last updated layers.

For more info see go/surface-flinger-scheduler and
go/content-fps-detection-in-scheduler

Test: Updating unit tests. Systrace.

Change-Id: I988a7a79e9a9f0f61674c9b637c5142db3336177
Bug: 127727337