Chrome Alarm Clear and ClearAll Updates

chrome.alarms.clear will now take an optional callback indicating if the
specified alarm was cleared. It will no longer post an error.

chrome.alarms.clearAll will also behave similarly. It will provide a
callback at the completion of clearAll indicating if all alarms were
cleared successfully.

BUG=352230

Review URL: https://codereview.chromium.org/205323002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@258526 0039d316-1c4b-4281-b951-d872f2087c98
3 files changed