Expose a way to obtain a unique ID for the current process.
Expose a way to obtain a unique ID for the current process.

BUG=501069,499332

Review URL: https://codereview.chromium.org/1181603007

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@197514 bbb929c8-8fbe-4397-9dbb-9b2b20218538

axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk