Accessibility/Doorhanger Keyboard Navigation

Mozilla bug: bug 653230, originally started in bug 616136.

The problem with the current implementation of the doorhanger keyboard navigation is as follows:

• When a doorhanger appears, it grabs keyboard focus and traps it inside of itself.
• In addition, an accessibility alert is generated, also telling the user about the doorhanger being present.

This behavior is undesired because if a doorhanger appears, much like the older popup notifications, the user may not necessarily want to interact with it right away. For example, they may not want to decide right away whether to save a password or not.

Proposed solution

• If the doorhanger appears, generate the alert as it is done now.
• Leave keyboard focus in the document and allow the user to review the newly loaded document as they desire.
• Implement Shift+F6 to focus the doorhanger and allow the user to tab between the text, menu button and the "close this message" button. (Note that Shift+F6 can be used to go to the doorhanger from the document if the user escaped out of it once already.
• A press of F6 should bring user back to document. (Note that this is already done.)

The thing that must be changed is the fact that the doorhanger should not grab focus once it pops up.

The thing that must be checked if Shift+F6 reliably goes from the document to the doorhanger if it is present after the above change has been made.