Revert of Move UndoStack from Page to Editor

Revert of Move UndoStack from Page to Editor (patchset #4 id:60001 of https://codereview.chromium.org/2110543008/ )

Reason for revert:
speculative revert to see whether this caused crbug.com/625736

Original issue's description:
> Move UndoStack from Page to Editor
>
> Blink currently maintains per-page undo stacks, leading to:
> - Security risks. A frame can directly manipulate content of another frame
> by running document.execCommand('undo'), allowing Javascript to bypass
> frame and even origin boundaries.
> - Inconsistent behaviors. Without OOPIF, all changes in a page can be undone
> by repeatedly invoking keyboard undo (CTRL+Z); With OOPIF, only those changes
> in the focused frame and its same-origin frames can be undone.
>
> Redos have analogous defects.
>
> This patch changes UndoStack from per-page to per-frame, so that undos and
> redos are consistently resolved by the frame where script is run or which
> gets focused.
>
> This patch also removes |UndoStack::didUnloadFrame()| since its only purpose
> is to filter out the undo steps for a particular frame, which no longer makes
> sense after undo stacks are made per-frame.
>
> BUG=349272, 549334
> TEST=editing/undo/undo-iframe-location-change.html
>
> Committed: https://crrev.com/6447f384cf6d95f70475798e3fd45b689316ce50
> Cr-Commit-Position: refs/heads/master@{#403653}

TBR=tkent@chromium.org,yosin@chromium.org,xiaochengh@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=349272, 549334
Committed: https://crrev.com/4fef5557cbf3bc2dbcf46ea386ef9243860be835
Cr-Commit-Position: refs/heads/master@{#403742}

[Kunihiko Sakamoto, 2016-07-05 05:01:01]

The CQ bit was checked by ksakamoto@chromium.org

[Kunihiko Sakamoto, 2016-07-05 05:01:01]

Created Revert of Move UndoStack from Page to Editor

[commit-bot: I haz the power, 2016-07-05 05:01:19]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-07-05 05:02:05]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-07-05 05:03:33]

Description was changed from

==========
Revert of Move UndoStack from Page to Editor (patchset #4 id:60001 of
https://codereview.chromium.org/2110543008/ )

Reason for revert:
speculative revert to see whether this caused crbug.com/625736

Original issue's description:
> Move UndoStack from Page to Editor
> 
> Blink currently maintains per-page undo stacks, leading to:
> - Security risks. A frame can directly manipulate content of another frame
> by running document.execCommand('undo'), allowing Javascript to bypass
> frame and even origin boundaries.
> - Inconsistent behaviors. Without OOPIF, all changes in a page can be undone
> by repeatedly invoking keyboard undo (CTRL+Z); With OOPIF, only those changes
> in the focused frame and its same-origin frames can be undone.
> 
> Redos have analogous defects.
> 
> This patch changes UndoStack from per-page to per-frame, so that undos and
> redos are consistently resolved by the frame where script is run or which
> gets focused.
> 
> This patch also removes |UndoStack::didUnloadFrame()| since its only purpose
> is to filter out the undo steps for a particular frame, which no longer makes
> sense after undo stacks are made per-frame.
> 
> BUG=349272,549334
> TEST=editing/undo/undo-iframe-location-change.html
> 
> Committed: https://crrev.com/6447f384cf6d95f70475798e3fd45b689316ce50
> Cr-Commit-Position: refs/heads/master@{#403653}

TBR=tkent@chromium.org,yosin@chromium.org,xiaochengh@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=349272,549334
==========

to

==========
Revert of Move UndoStack from Page to Editor (patchset #4 id:60001 of
https://codereview.chromium.org/2110543008/ )

Reason for revert:
speculative revert to see whether this caused crbug.com/625736

Original issue's description:
> Move UndoStack from Page to Editor
>
> Blink currently maintains per-page undo stacks, leading to:
> - Security risks. A frame can directly manipulate content of another frame
> by running document.execCommand('undo'), allowing Javascript to bypass
> frame and even origin boundaries.
> - Inconsistent behaviors. Without OOPIF, all changes in a page can be undone
> by repeatedly invoking keyboard undo (CTRL+Z); With OOPIF, only those changes
> in the focused frame and its same-origin frames can be undone.
>
> Redos have analogous defects.
>
> This patch changes UndoStack from per-page to per-frame, so that undos and
> redos are consistently resolved by the frame where script is run or which
> gets focused.
>
> This patch also removes |UndoStack::didUnloadFrame()| since its only purpose
> is to filter out the undo steps for a particular frame, which no longer makes
> sense after undo stacks are made per-frame.
>
> BUG=349272,549334
> TEST=editing/undo/undo-iframe-location-change.html
>
> Committed: https://crrev.com/6447f384cf6d95f70475798e3fd45b689316ce50
> Cr-Commit-Position: refs/heads/master@{#403653}

TBR=tkent@chromium.org,yosin@chromium.org,xiaochengh@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=349272,549334

Committed: https://crrev.com/4fef5557cbf3bc2dbcf46ea386ef9243860be835
Cr-Commit-Position: refs/heads/master@{#403742}
==========

[commit-bot: I haz the power, 2016-07-05 05:03:34]

Patchset 1 (id:??) landed as
https://crrev.com/4fef5557cbf3bc2dbcf46ea386ef9243860be835
Cr-Commit-Position: refs/heads/master@{#403742}

[tkent, 2016-07-05 05:13:19]

lgtm