Improve handling of "search" fields.

[duhrer]

Currently, operating a search input works something like:

1. Navigate to the search field.
2. Click to open the search keyboard.
3. Enter search text using the onscreen keyboard.
4. Close the modal using the close button (returns focus to the text input).
5. Navigate to the submit button for the associate search form.
6. Click the submit button.

Since we know it's a search, we could instead:

1. Navigate to the search field.
2. Click to open the search keyboard.
3. Enter search text using the onscreen keyboard.
4. Click "Search" within the modal to close the modal and start the search.

Once the user hits "Search", we would:

1. Set the value of the original input.
2. Submit the enclosing form automatically.