Revert of Re-re-enable the activation behavior of media elements (click to play/pause)

Revert of Re-re-enable the activation behavior of media elements (click to play/pause) (patchset #2 id:20001 of https://codereview.chromium.org/829393004/)

Reason for revert:
On Android:
1. The entire video is now clickable, leading more often to ambigous
   touches and zooming.
2. When the controls are not visible, touching the video will both pause
   the video and show the controls, where they would previously only
   show the controls.

Original issue's description:
> Re-re-enable the activation behavior of media elements (click to play/pause)
> 
> The previous attempt broke the overlay play button:
> https://codereview.chromium.org/830183005/#msg15
> 
> Drop the changes to MediaControlOverlayPlayButtonElement and add a test.
> 
> BUG=354746
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=188233

TBR=fs@opera.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=354746
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=188869

[philipj_slow, 2015-01-23 09:48:19]

Created Revert of Re-re-enable the activation behavior of media elements (click
to play/pause)

[commit-bot: I haz the power, 2015-01-23 09:49:11]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/867063003/1

[commit-bot: I haz the power, 2015-01-23 09:49:49]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=188869