Get rid of AXScrollView and AXScrollbar

Get rid of AXScrollView and AXScrollbar

They're an unnecessary abstraction, leftover from WebKit and just getting in
the way. Now an iframe's accessibility object has the child frame document's
accessibility object as its immediate child. This depends on previous changes
that put all of the document scroll attributes and methods on the document's
AXObject rather than on its parent AXScrollView.

This also eliminates an arbitrary and confusing difference between
local and remote frames in the accessibility tree.

BUG=484878
Committed: https://crrev.com/d79d97eba65b5fd1303b1ce18d6ac4bab9dce970
Cr-Commit-Position: refs/heads/master@{#370342}

[dmazzoni, 2016-01-06 18:48:10]

dmazzoni@chromium.org changed reviewers:
+ dglazkov@chromium.org, je_julie.kim@chromium.org

[dglazkov, 2016-01-06 18:55:19]

lgtm

[je_julie, 2016-01-07 06:56:03]

I'm happy that we have healthier code than before.
LGTM!

https://codereview.chromium.org/1564863002/diff/1/third_party/WebKit/Source/c...
File third_party/WebKit/Source/core/dom/AXObjectCache.h (right):

https://codereview.chromium.org/1564863002/diff/1/third_party/WebKit/Source/c...
third_party/WebKit/Source/core/dom/AXObjectCache.h:130: // Called when scroll
bars are added / removed (as the view resizes).
nit, this comment seems to be added for handleScrollbarUpdate(FrameView*) API
and we can remove it as well.

[dmazzoni, 2016-01-20 05:38:47]

The CQ bit was checked by dmazzoni@chromium.org

[dmazzoni, 2016-01-20 05:38:47]

The patchset sent to the CQ was uploaded after l-g-t-m from
je_julie.kim@chromium.org, dglazkov@chromium.org
Link to the patchset: https://codereview.chromium.org/1564863002/#ps40001
(title: "Fix Android expectation")

[commit-bot: I haz the power, 2016-01-20 05:39:06]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1564863002/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1564863002/40001

[commit-bot: I haz the power, 2016-01-20 08:48:20]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2016-01-20 08:49:13]

Description was changed from

==========
Get rid of AXScrollView and AXScrollbar

They're an unnecessary abstraction, leftover from WebKit and just getting in
the way. Now an iframe's accessibility object has the child frame document's
accessibility object as its immediate child. This depends on previous changes
that put all of the document scroll attributes and methods on the document's
AXObject rather than on its parent AXScrollView.

This also eliminates an arbitrary and confusing difference between
local and remote frames in the accessibility tree.

BUG=484878
==========

to

==========
Get rid of AXScrollView and AXScrollbar

They're an unnecessary abstraction, leftover from WebKit and just getting in
the way. Now an iframe's accessibility object has the child frame document's
accessibility object as its immediate child. This depends on previous changes
that put all of the document scroll attributes and methods on the document's
AXObject rather than on its parent AXScrollView.

This also eliminates an arbitrary and confusing difference between
local and remote frames in the accessibility tree.

BUG=484878

Committed: https://crrev.com/d79d97eba65b5fd1303b1ce18d6ac4bab9dce970
Cr-Commit-Position: refs/heads/master@{#370342}
==========

[commit-bot: I haz the power, 2016-01-20 08:49:14]

Patchset 3 (id:??) landed as
https://crrev.com/d79d97eba65b5fd1303b1ce18d6ac4bab9dce970
Cr-Commit-Position: refs/heads/master@{#370342}