media: Remove kRAConsentGranted pref.

media: Remove kRAConsentGranted pref.

Now protected media identifier content setting is not synced, we don't need
kRAConsentGranted pref any more. Whether we should prompt user solely depends on
the content setting status.

TBR=sky@chromium.org
BUG=468569
TEST=Manually tested.

Committed: https://crrev.com/0ef984eae4e562fc9e0b7ae23f9a4de778e3881f
Cr-Commit-Position: refs/heads/master@{#323779}

[xhwang, 2015-03-23 16:48:02]

xhwang@chromium.org changed reviewers:
+ ddorwin@chromium.org

[xhwang, 2015-03-23 16:48:15]

PTAL

[xhwang, 2015-03-23 16:48:57]

xhwang@chromium.org changed reviewers:
+ dkrahn@chromium.org

[xhwang, 2015-03-23 16:49:19]

xhwang@chromium.org changed required reviewers:
+ ddorwin@chromium.org

[ddorwin, 2015-03-23 17:23:21]

lgtm

[ddorwin, 2015-04-02 18:01:40]

The CL originally in the description (I removed it) has landed. This is now
blocked on a second CL.

This is ready to commit after https://codereview.chromium.org/1004733003/ (DONE)
and https://codereview.chromium.org/1005303003/.

[xhwang, 2015-04-03 16:59:25]

rebase only

[xhwang, 2015-04-03 17:00:46]

xhwang@chromium.org changed reviewers:
+ sky@chromium.org

[xhwang, 2015-04-03 17:01:21]

TBRing sky@ for removing a line in chrome/browser/prefs/browser_prefs.cc.

[xhwang, 2015-04-03 17:48:30]

The CQ bit was checked by xhwang@chromium.org

[xhwang, 2015-04-03 17:48:31]

The patchset sent to the CQ was uploaded after l-g-t-m from ddorwin@chromium.org
Link to the patchset: https://codereview.chromium.org/1024563005/#ps20001
(title: "rebase only")

[commit-bot: I haz the power, 2015-04-03 17:49:05]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1024563005/20001

[commit-bot: I haz the power, 2015-04-03 18:30:05]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-04-03 20:39:22]

Patchset 2 (id:??) landed as
https://crrev.com/0ef984eae4e562fc9e0b7ae23f9a4de778e3881f
Cr-Commit-Position: refs/heads/master@{#323779}