Include viewport visibility checks for autoplay experiment.

LayoutTests/media/video-autoplay-experiment-modes-expected.txt

 CONSOLE WARNING: Failed to execute 'play' on 'HTMLMediaElement': API can only be initiated by a user gesture.
 CONSOLE WARNING: Failed to execute 'play' on 'HTMLMediaElement': API can only be initiated by a user gesture.
 CONSOLE WARNING: Failed to execute 'play' on 'HTMLMediaElement': API can only be initiated by a user gesture.
 CONSOLE WARNING: Failed to execute 'play' on 'HTMLMediaElement': API can only be initiated by a user gesture.
 CONSOLE WARNING: Failed to execute 'play' on 'HTMLMediaElement': API can only be initiated by a user gesture.
 CONSOLE WARNING: Failed to execute 'play' on 'HTMLMediaElement': API can only be initiated by a user gesture.
 CONSOLE WARNING: Failed to execute 'play' on 'HTMLMediaElement': API can only be initiated by a user gesture.
-CONSOLE WARNING: Failed to execute 'play' on 'HTMLMediaElement': API can only be initiated by a user gesture.
-CONSOLE WARNING: Failed to execute 'play' on 'HTMLMediaElement': API can only be initiated by a user gesture.
 END OF TEST
   Check if the autoplay gesture override experiment works.  There are a lot
   of config options, so this test just runs all of them.
 
   The "results" table contains one row per config tested.
   == Test Inputs ==
   #      - config number, in case you'd like to run just one.
   Flags  - autoplay experiment setting being tested.
                a      - "foraudio"
                v      - "forvideo"
+               V      - "ifviewport"
                M      - "ifmuted"
                p      - "playmuted"
-               For example, EM means "enabled-ifmuted".
+               For example, vM means '-forvideo-ifmuted".
                This test does not check -ifmobile since that check always
                fails outside of android.
   Type   - audio or video element?
                audio  - 
-#       Flags   Type    Play w/ Mute    Played? Muted?
-0               video   none    none    no      -
-1               audio   none    none    no      -
-2       v       video   none    none    no      -
-3       v       audio   none    none    no      -
-4       vM      video   none    none    no      -
-5       vM      audio   none    none    no      -
-6       vp      video   none    none    no      -
-7       vp      audio   none    none    no      -
-8       a       video   none    none    no      -
-9       a       audio   none    none    no      -
-10              video   attr    none    no      -
-11              audio   attr    none    no      -
-12      v       video   attr    none    played  unmuted
-13      v       audio   attr    none    no      -
-14      vM      video   attr    none    no      -
-15      vM      audio   attr    none    no      -
-16      vp      video   attr    none    played  muted
-17      vp      audio   attr    none    no      -
-18      a       video   attr    none    no      -
-19      a       audio   attr    none    played  unmuted
-20              video   play()  none    no      -
-21              audio   play()  none    no      -
-22      v       video   play()  none    played  unmuted
-23      v       audio   play()  none    no      -
-24      vM      video   play()  none    no      -
-25      vM      audio   play()  none    no      -
-26      vp      video   play()  none    played  muted
-27      vp      audio   play()  none    no      -
-28      a       video   play()  none    no      -
-29      a       audio   play()  none    played  unmuted
-34      vM      video   none    attr    no      -
-35      vM      audio   none    attr    no      -
-44      vM      video   attr    attr    played  muted
-45      vM      audio   attr    attr    no      -
-54      vM      video   play()  attr    played  muted
-55      vM      audio   play()  attr    no      -
-64      vM      video   none    js      no      -
-65      vM      audio   none    js      no      -
-74      vM      video   attr    js      played  muted
-75      vM      audio   attr    js      no      -
-84      vM      video   play()  js      played  muted
-85      vM      audio   play()  js      no      -
+#       Flags   Type    Play w/ Mute    View    Early?  Played? Muted?
+0               video   none    none    onscree -       no      -
+2       v       video   none    none    onscree -       no      -
+4       vV      video   none    none    onscree -       no      -
+6       vVM     video   none    none    onscree -       no      -
+8       vVp     video   none    none    onscree -       no      -
+14              video   attr    none    onscree -       no      -
+16      v       video   attr    none    onscree -       played  unmuted
+18      vV      video   attr    none    onscree -       played  unmuted
+20      vVM     video   attr    none    onscree -       no      -
+22      vVp     video   attr    none    onscree -       played  muted
+24      a       video   attr    none    onscree -       no      -
+26      aV      video   attr    none    onscree -       no      -
+28              video   play()  none    onscree -       no      -
+30      v       video   play()  none    onscree -       played  unmuted
+32      vV      video   play()  none    onscree -       played  unmuted
+34      vVM     video   play()  none    onscree -       no      -
+36      vVp     video   play()  none    onscree -       played  muted
+48      vVM     video   none    attr    onscree -       no      -
+62      vVM     video   attr    attr    onscree -       played  muted
+76      vVM     video   play()  attr    onscree -       played  muted
+90      vVM     video   none    js      onscree -       no      -
+104     vVM     video   attr    js      onscree -       played  muted
+118     vVM     video   play()  js      onscree -       played  muted
+140             video   attr    none    scroll  no      no      -
+141             audio   attr    none    scroll  no      no      -
+142     v       video   attr    none    scroll  yes     played  unmuted
+144     vV      video   attr    none    scroll  no      played  unmuted
+148     vVp     video   attr    none    scroll  no      played  muted
+151     a       audio   attr    none    scroll  yes     played  unmuted
+153     aV      audio   attr    none    scroll  no      played  unmuted
+154             video   play()  none    scroll  no      no      -
+155             audio   play()  none    scroll  no      no      -
+156     v       video   play()  none    scroll  yes     played  unmuted
+158     vV      video   play()  none    scroll  no      played  unmuted
+162     vVp     video   play()  none    scroll  no      played  muted
+165     a       audio   play()  none    scroll  yes     played  unmuted
+167     aV      audio   play()  none    scroll  no      played  unmuted
+266             video   attr    none    offscre -       no      -
+268     v       video   attr    none    offscre -       played  unmuted
+270     vV      video   attr    none    offscre -       no      -
+274     vVp     video   attr    none    offscre -       no      -
+