GitLab

Fixed tile deletion functionality. The id of the tile was not being
obtained correctly.

Also fixed various accessibility issues:
- Keyboard focus will start on the first input field of the edit
  dialog.
- The iframes now have titles instead of "frame 0".
- The "x" button on a tile will no longer remain visible after clicking
  and releasing with a mouse.
- The button labels for screen readers are now applied correctly.
- "Restore all" is now "Restore default shortcuts" in the shortcut
  removed notification.
- If custom links is enabled, pressing "backspace" or "delete" while
  the shortcut is focused will now delete the shortcut.

Also adjusted variable names to match their CSS name.

Bug: 871663, 864357
Change-Id: I10135be42d9525931077daf0b7c859c60dd59e89
Reviewed-on: https://chromium-review.googlesource.com/1166028Reviewed-by: Mathieu Perreault <mathp@chromium.org>
Commit-Queue: Kristi Park <kristipark@chromium.org>
Cr-Commit-Position: refs/heads/master@{#581374}