Delete mediaPlaybackRequiresUserGesture

Source/core/frame/Settings.in

 # Defines properties which are available on the Settings object.
 #
 # Please think carefully before adding a new Setting.  Some questions to
 # consider are:
 # - Should this be a RuntimeEnabledFeature instead? Settings are for things
 #   which we support either values of at runtime.  Features are set at renderer
 #   process startup and are never changed. Features also tend to be set to a
 #   value based on the platform or the stability of the code in question, where
 #   as settings both codepaths need to be stable.
 # - How will you ensure test coverage of all relevant values of your setting?
@@ skipping 103 matching lines @@
 
 asynchronousSpellCheckingEnabled initial=false
 
 hyperlinkAuditingEnabled initial=false
 allowDisplayOfInsecureContent initial=true
 allowRunningOfInsecureContent initial=true
 # FIXME: Remove this temporary flag. See crbug.com/366483 for the target
 # milestone.
 allowConnectingInsecureWebSocket initial=false
 mediaControlsOverlayPlayButtonEnabled initial=false
-mediaPlaybackRequiresUserGesture initial=false
 
 scrollAnimatorEnabled initial=true
 
 shouldRespectImageOrientation initial=false
 
 # Limited use by features which behave differently depending on the input
 # devices available.  For example, the pointer and hover media queries.
 # Note that we need to be careful when basing behavior or UI on this -
 # just because a device is present doesn't mean the user cares about it
 # or uses it (i.e. Chromebook Pixel users generally don't want to give up
@@ skipping 131 matching lines @@
 
 # This value indicates the maximum number of bytes a document is allowed
 # to transmit in Beacons (via navigator.sendBeacon()) -- Beacons are
 # intended to be smaller payloads transmitted as a page is unloading, not
 # a general (one-way) network transmission API.
 # The spec ( https://dvcs.w3.org/hg/webperf/raw-file/tip/specs/Beacon/Overview.html )
 # does not proscribe an upper limit, but allows for it -- the underlying
 # API will return 'false' in that case.
 maxBeaconTransmission type=int, initial=16384