CB-6047 Fix online sometimes getting in a bad state on page transitions.

The online bridge toggles between on & off. Turns out that starting with
Android 4.3, navigation resets the online state, so the code had a 50/50
chance of being caught in the wrong state.

We now forcefully reset the online state on page transitions.

(cherry picked from commit a2f8c9c75b4fa2d0ce787d8b75bf7f161d6699fc)
RTC 35749: add IBM-MODIFICATIONS.txt after cherry-pick