demo keyboard app: implement autocorrect, etc.

autocorrect and word suggestions

make backspace key autorepeat and implement caps lock
Merge pull request #13896 from davidflanagan/demokbdim

demo keyboard app: implement autocorrect, etc.
Bug 935087 - [Download Manager] Download list view skeleton
Bug 935070 - [Download Manager] New shared component DownloadItem
Bug 935088 - [Download Manager] Download list app behavior