The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/d9e076c4780e0bcb4af6a257407f006c44a3a976

commit d9e076c4780e0bcb4af6a257407f006c44a3a976
Author: xiaochengh <xiaochengh@chromium.org>
Date: Wed Jan 18 12:13:14 2017

Move EditCommand::starting/endingSelection() to CompositeEditCommand (1/2)

Currently, starting and ending selections are defined for all EditCommand,
but are used by only CompositeEditCommand; SimpleEditCommand does not use
them.

Hence, this patch moves the two selections from EditCommand to
CompositeEditCommand, so that the construction of SimpleCommand becomes
simpler.

As EditCommand::setParent modifies starting and ending selection, this
patch turns it into a virtual function, and overrides it with
CompositeEditCommand::setParent to modify the selections.

This patch also removes a redundant static function undoStepIfPossible()
from EditCommand.cpp.

BUG= 682137 
TEST=n/a; no behavior change

Review-Url: https://codereview.chromium.org/2641803002
Cr-Commit-Position: refs/heads/master@{#444338}

[modify] https://crrev.com/d9e076c4780e0bcb4af6a257407f006c44a3a976/third_party/WebKit/Source/core/editing/commands/CompositeEditCommand.cpp
[modify] https://crrev.com/d9e076c4780e0bcb4af6a257407f006c44a3a976/third_party/WebKit/Source/core/editing/commands/CompositeEditCommand.h
[modify] https://crrev.com/d9e076c4780e0bcb4af6a257407f006c44a3a976/third_party/WebKit/Source/core/editing/commands/EditCommand.cpp
[modify] https://crrev.com/d9e076c4780e0bcb4af6a257407f006c44a3a976/third_party/WebKit/Source/core/editing/commands/EditCommand.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/2742a8b3bdc414e596a9382a3b6959c0c4e95f93

commit 2742a8b3bdc414e596a9382a3b6959c0c4e95f93
Author: xiaochengh <xiaochengh@chromium.org>
Date: Thu Jan 19 01:28:05 2017

Move EditCommand::starting/endingSelection() to CompositeEditCommand (2/2)

BUG= 682137 

Review-Url: https://codereview.chromium.org/2645453002
Cr-Commit-Position: refs/heads/master@{#444587}

[modify] https://crrev.com/2742a8b3bdc414e596a9382a3b6959c0c4e95f93/third_party/WebKit/Source/core/editing/commands/CompositeEditCommand.cpp
[modify] https://crrev.com/2742a8b3bdc414e596a9382a3b6959c0c4e95f93/third_party/WebKit/Source/core/editing/commands/EditCommand.cpp