Build libaddressinput in Chrome for requestAutocomplete().

This CL:
- creates a chromium-specific:
 * third_party/libaddressinput/
  * chromium/util/
   - json.cc (chromium-specific json reader)
   - json.h (matches src/cpp/src/util/json.h's interface)
  - libaddressinput.gyp (chromium-specific .gyp file)
- builds and runs a new test target named libaddressinput_unittests

R=rouslan@chromium.org
BUG=317837

Review URL: https://codereview.chromium.org/68323005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@236996 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 236996