Port process_coverage to annotator.
Port process_coverage to annotator.

This change is part of the move from master-parsed perf to slave.

BUG=158683


Review URL: https://chromiumcodereview.appspot.com/12221007

git-svn-id: 239fca9b83025a0b6f823aeeca02ba5be3d9fd76@180617 0039d316-1c4b-4281-b951-d872f2087c98

eunchong/build,eunchong/build,eunchong/build,eunchong/build