Merge pull request #20259 from RudyLu/ringtone/Bug1023045-Sound_backButton

Bug 1023045 - [Settings][Ringtone][V2.0] The "<" icon of
 r=jimporter.
Merge pull request #20268 from alivedise/bugzilla/1022943/swipe-navigation-icon

Bug 1022943 - Update swipe navigation icon, r=arthur
Merge pull request #20252 from hfiguiere/bug1019037

Bug 1019037 - Set a starting event for the call log test. r=etienne,eli