Revert 284065 "Revert of Revert of Migrate accessibility from Re..."

Revert 284065 "Revert of Revert of Migrate accessibility from Re..."

Reason for revert:
Use-after-free raised on MFYI waterfall.
BUG=395670
> Revert of Revert of Migrate accessibility from RenderView to RenderFrame. (https://codereview.chromium.org/407493002/)
> 
> Reason for revert:
> Reverting the revert. This didn't break the tree; it's still broken without the patch. :(
> 
> Sorry for the noise!
> 
> Original issue's description:
> > 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
> 
> TBR=creis@chromium.org,nick@chromium.org,nasko@chromium.org,jam@chromium.org,dtseng@chromium.org,jschuh@chromium.org,tsepez@chromium.org,kenrb@chromium.org,dmazzoni@chromium.org
> NOTREECHECKS=true
> NOTRY=true
> 
> Review URL: https://codereview.chromium.org/407493004

TBR=mkwst@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=284470

[Derek Bruening, 2014-07-21 19:14:07]

Committed patchset #1 manually as r284470 (tree was closed).