Revert of Turn webspeech on/off when tab goes fore/background

Revert of Turn webspeech on/off when tab goes fore/background (https://codereview.chromium.org/415433002/)

Reason for revert:
Tentatively reverting because [1] has been consistently crashing in 2 layout tests ever since this landed[2], and this is the more likely looking of the two CLs on the blamelist:

http://build.chromium.org/f/chromium/perf/dashboard/ui/changelog.html?url=%2Ftrunk%2Fsrc&range=285071%3A285072&mode=html

http://build.chromium.org/f/chromium/perf/dashboard/ui/changelog_blink.html?url=%2Ftrunk&range=178788%3A178788&mode=html

[1]: http://build.chromium.org/p/chromium.webkit/builders/WebKit%20Android%20%28Nexus4%29

[2]: http://build.chromium.org/p/chromium.webkit/builders/WebKit%20Android%20%28Nexus4%29/builds/16889

Original issue's description:
> Turn webspeech off when tab goes background
> 
> This change adds a toggle to turn webspeech off when tab goes background.
> And further request to turn media capture devices on will be denied.
> So Both WebRTC and webSpeech won't be able to initiate new requests when tab is in background.
> 
> BUG=396054
> R=dalecurtis@chromium.org, jam@chromium.org
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=285072

TBR=jam@chromium.org,juberti@chromium.org,xians@chromium.org,dalecurtis@google.com,dalecurtis@chromium.org,qinmin@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=396054
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=285208

[johnme, 2014-07-24 12:25:53]

Created Revert of Turn webspeech on/off when tab goes fore/background

[commit-bot: I haz the power, 2014-07-24 12:27:30]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/johnme@chromium.org/416053002/1

[commit-bot: I haz the power, 2014-07-24 12:29:22]

Change committed as 285208