Effects: add new effect volume flag

Add new effect flag for monitoring requested volume from
audio framework.

Bug: 123251705
Test: on/off equalizer on spotify/google music
      switch songs with equalizer

Change-Id: If007ee4a2fdac56636440c010a4b3e8b526de721
Signed-off-by: Jasmine Cha <chajasmine@google.com>
1 file changed