Merge changes I5e56f17f,Ie3748b6c,I4e1d56a8 am: cea14958d2 am: 71c062f40a
am: ebb08fb9a6

* commit 'ebb08fb9a6653a35823bf26ca3ec6af3d0b81dca':
  adb: switch the socket list mutex to a recursive_mutex.
  adb: clang-format sockets.cpp.
  adb: add implementations of mutex, recursive_mutex.

Change-Id: Id9c9284fd3d13abd183d7be6cd96c3c1cf589350