Follow-on fixes and naming changes for https://codereview.chromium.org/12086077/

BUG=172573
Review URL: https://codereview.chromium.org/12177018

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@180600 0039d316-1c4b-4281-b951-d872f2087c98
void PluginServiceImpl::RegisterFilePathWatcher(FilePathWatcher* watcher,
                                                const FilePath& path) {
  bool result = watcher->Watch(path, false,
                               base::Bind(&NotifyPluginDirChanged));
  DCHECK(result);
}

void PluginServiceImpl::RegisterFilePathWatcher(FilePathWatcher* watcher,
                                                const FilePath& path) {
  bool result = watcher->Watch(path, false,
                               base::Bind(&NotifyPluginDirChanged));
  DCHECK(result);
}
