This patch factors out a lot of the basic protocol code: sending OKAY,
sending FAIL, and sending a length-prefixed string.
ADB_TRACE has been non-optional for a long time, so let's just remove
the #ifs.
Also actually build the device tracker test tool (and remove its duplicate).
Bug: http://b/20666660
Change-Id: I6c7d59f18707bdc62ca69dea45547617f9f31fc6
Renamed readx/writex to ReadFdExactly/WriteFdExactly respectively.
These read/write a full fixed-size buffer. If the whole buffer cannot
be read/written, these functions return an error.
Rename write_string to WriteStringFully.
Move the TEMP_FAILURE_RETRY definition in sysdeps.h out of the
!Windows section. It seems Windows won't actually interrupt a call,
but it's easier to just define it than to #ifdef each call.
Change-Id: Ia8ddffa2a52764a2f9a281c96c937660e002b9b9
