a18661d592
1. We used to show a single notificaiton for every print job but this is against th UX guidelines. Since we have to lead by example, this change adds coalescing of multiple notifications. bug:11155212 2. Print job state callback in the PrintManager now correctly invoked on the main thread. bug:10983508 Change-Id: I906e9e62198fa37cb4d2f71fce07ed475d61e1bd