Revert of Migrate accessibility from RenderView to RenderFrame.

Revert of Migrate accessibility from RenderView to RenderFrame. (https://codereview.chromium.org/273423004/)

Reason for revert:
Speculative revert to fix XP bots.

XP bots started crashing http://build.chromium.org/p/chromium.win/builders/XP%20Tests%20%281%29/builds/32011 and http://build.chromium.org/p/chromium.win/builders/XP%20Tests%20%282%29/builds/34677

This CL is the most suspicious in the range. If it doesn't fix the bots, I'll unrevert it.

Original issue's description:
> Migrate accessibility from RenderView to RenderFrame and RVH to RFH.
> 
> In preparation for out-of-process iframes, move almost all accessibility
> functionality from RenderView to RenderFrame, and from RVHI and RWHI
> to RFHI.
> 
> In addition, the accessibility mode is moved to WebContents, and changing
> the mode triggers changing it on all frames.
> 
> BUG=368298
> R=jam@chromium.org, kenrb@chromium.org, nick@chromium.org
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=283994

TBR=dmazzoni@chromium.org
NOTRY=true

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=284032

[Mike West, 2014-07-18 07:38:16]

Created Revert of Migrate accessibility from RenderView to RenderFrame.

[commit-bot: I haz the power, 2014-07-18 07:39:22]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/mkwst@chromium.org/407493002/1

[commit-bot: I haz the power, 2014-07-18 07:39:23]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-07-18 07:39:24]

No LGTM from a valid reviewer yet. Only full committers are accepted.
Even if an LGTM may have been provided, it was from a non-committer or
a provisional committer, _not_ a full super star committer.
See http://www.chromium.org/getting-involved/become-a-committer
Note that this has nothing to do with OWNERS files.

[Mike West, 2014-07-18 07:40:30]

The CQ bit was checked by mkwst@chromium.org

[commit-bot: I haz the power, 2014-07-18 07:41:12]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/mkwst@chromium.org/407493002/1

[commit-bot: I haz the power, 2014-07-18 07:42:32]

Change committed as 284032

[Mike West, 2014-07-18 12:28:34]

A revert of this CL has been created in
https://codereview.chromium.org/407493004/ by mkwst@chromium.org.

The reason for reverting is: Reverting the revert. This didn't break the tree;
it's still broken without the patch. :(

Sorry for the noise!.