Merge changes I5e56f17f,Ie3748b6c,I4e1d56a8 am: cea14958d2
am: 71c062f40a

* commit '71c062f40ac9ac5175f55bce03ce0cb8eb540710':
  adb: switch the socket list mutex to a recursive_mutex.
  adb: clang-format sockets.cpp.
  adb: add implementations of mutex, recursive_mutex.

Change-Id: Icd8a74f1052f7b4c4616ddf23b65c7208195202c