(bug 37510) Clicking 'donate to Wikipedia' gives no warning message before leaving the page <OH-AFT>

This will ask for confirmation if moving away from the page once a user has started writing feedback, but has not yet submitted it.

Bug: 37510
Change-Id: Icdcb0ad36da12bd2efbc2e16a2301946bac315df
Merge "(bug 37510) Clicking 'donate to Wikipedia' gives no warning message before leaving the page <OH-AFT>"