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
Review-Url: https://codereview.chromium.org/2127463002
Cr-Commit-Position: refs/heads/master@{#403742}
9 files changed
