Restructure public side of geometry service.

Restructure public side of geometry service.

This CL goes from this:
  //mojo/services/public/cpp/geometry
  //mojo/services/public/interfaces/geometry

to this:
  //mojo/services/geometry/public/cpp
  //mojo/services/geometry/public/interfaces

This CL also makes the Mojo-side changes required to roll this change into
Chromium.

TBR=beng

Committed: https://chromium.googlesource.com/external/mojo/+/f684109bb1a2cdaa0de6e1d9204dfe20f3c8e9de

[blundell, 2014-12-10 16:56:48]

Committed patchset #3 (id:40001) manually as
f684109bb1a2cdaa0de6e1d9204dfe20f3c8e9de (presubmit successful).