Simplify SendWireMessage.
Simplify SendWireMessage.

The old code was a remnant of the time when we used sendmsg.
This gets rid of the loop.

Change-Id: Ife31b0e2b5970d347335178c7bea38e42d7ebb05
Bug: 160388760
google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto