Merge remote-tracking branch 'aosp/upstream' into master

* aosp/upstream:
  Add proptools.BoolDefault and proptools.StringDefault
  Reduce maximum goroutine count
  Add Patch and PatchList for making textual changes
  Make End() return the position after the node

Test: m checkbuild
Change-Id: I70b44507135ed0c36458db0d4630402b6e8990bd