audio policy: session routes continued.

- Clear session routes when client process dies.
- Enforce the route only when the requesting session is active.
- Fix requested route not working if an output mix change is required
(e.g forcing to SPEAKER when the default route is USB or A2DP).
- Make sure all sessions sharing the strategy with a rerouted session
have the same route (needed for volume control consistency)

Change-Id: I0ab347a8fb97e73e2c5965374544c5f4fe509ef1
diff --git a/include/media/IAudioPolicyService.h b/include/media/IAudioPolicyService.h
index 56a1dc6..ee462a0 100644
--- a/include/media/IAudioPolicyService.h
+++ b/include/media/IAudioPolicyService.h
@@ -62,6 +62,7 @@
                                         audio_io_handle_t *output,
                                         audio_session_t session,
                                         audio_stream_type_t *stream,
+                                        uid_t uid,
                                         uint32_t samplingRate = 0,
                                         audio_format_t format = AUDIO_FORMAT_DEFAULT,
                                         audio_channel_mask_t channelMask = 0,
@@ -80,6 +81,7 @@
     virtual status_t  getInputForAttr(const audio_attributes_t *attr,
                               audio_io_handle_t *input,
                               audio_session_t session,
+                              uid_t uid,
                               uint32_t samplingRate,
                               audio_format_t format,
                               audio_channel_mask_t channelMask,