Add a watchlist for clipboard/drag and drop.
Add a watchlist for clipboard/drag and drop.

R=eseidel@chromium.org

Review URL: https://codereview.chromium.org/186283003

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@168399 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