Add LocalFileChangeTracker database to record non-synced dirty files

BUG=148886
TEST=content_unittests --gtest_filter=\*LocalFileChangeTrackerTest\*

Review URL: https://chromiumcodereview.appspot.com/10966003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@158791 0039d316-1c4b-4281-b951-d872f2087c98
3 files changed