Baseline: 1b0cb1fa

Important changes:

  - Soft deprecate bazel startup option --write_command_log. User
    should switch to use command option with the same name or look at
    the build event messages.
  - Add better defaults for mobile-install flags

This release contains contributions from many people at Google, as well as Alex Fax, Chi Wang, David Sanderson, Fabian Meumertzheim, Peter Li, PikachuHy.