Loading spinner sometimes stays on when returning to SampleActivity from TwoToastersActivity

[carltonwhitehead]

Steps to reproduce

1. Start sample app in Normal Mode
2. Zoom until Two Toasters office is drawn as a single marker
3. Tap the Two Toasters office marker to open the TwoToastersActivity
4. Navigate back to SampleActivity (hardware back button or ActionBar up)
5. If loading spinner is not already spinning indefinitely, repeat steps 3 and 4 (sometimes it doesn't happen on the first try, but will on the second as long as the camera position doesn't change)

Expected results

Either no loading spinner is shown at all, or the loading spinner is only visible very briefly (substantially less than one second)

Actual results

The loading spinner is shown forever, or until the camera position is changed