Floss: Implement Pandora HFP profile (part2).

Bug: 301000117
Bug: 301000133
Bug: 300942860
Bug: 301000134
Bug: 301000127
Bug: 301000129
Bug: 300954039
Bug: 301000131
Bug: 300954045
Bug: 301036158
Bug: 301036160

Test: mma packages/modules/Bluetooth && pts-bot HFP
Tag: #floss
Flag: EXEMPT floss only changes
Change-Id: I648da8963227c38f4725991053a062c7ed61d9bf