DevTools: search in files: can't click to search text edit if the search pane is small.

click was captured by .empty-view with text "No matches found"

BUG=415123
NOTRY=true

Review URL: https://codereview.chromium.org/555553006

git-svn-id: svn://svn.chromium.org/blink/trunk@182233 bbb929c8-8fbe-4397-9dbb-9b2b20218538