Merge changes I5e56f17f,Ie3748b6c,I4e1d56a8
am: cea14958d2

* commit 'cea14958d2903f136f8874238ccff4da1b0d38d9':
  adb: switch the socket list mutex to a recursive_mutex.
  adb: clang-format sockets.cpp.
  adb: add implementations of mutex, recursive_mutex.

Change-Id: I8ec365c99dbc1dc402d62a8401df937ae6ae3a6b