Reland of VariableProxy: when cloning, don't even think about creating dangling references.

Reland of VariableProxy: when cloning, don't even think about creating dangling references. (patchset #1 id:1 of https://codereview.chromium.org/2368303002/ )

Reason for revert:
wrong CL

Original issue's description:
> Revert of VariableProxy: when cloning, don't even think about creating dangling references. (patchset #1 id:1 of https://codereview.chromium.org/2368253002/ )
>
> Reason for revert:
> Needed for  https://codereview.chromium.org/2373443003/
>
> Original issue's description:
> > VariableProxy: when cloning, don't even think about creating dangling references.
> >
> > The code path for cloning resolved VariableProxys (into a different
> > Zone) was never hit, but if it was, it would create a dangling
> > reference, since the Variable would stay in the original Zone.
> >
> > Kudos to verwaest@ for finding this!
> >
> > R=verwaest@chromium.org
> > BUG=
> >
> > Committed: https://crrev.com/fd429bdb9e70cb8c4f8a4bbef0806e008c60440c
> > Cr-Commit-Position: refs/heads/master@{#39723}
>
> TBR=verwaest@chromium.org,marja@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=
>
> Committed: https://crrev.com/8edf2905693a2b486a97a0547ec53bb552f7db15
> Cr-Commit-Position: refs/heads/master@{#39726}

TBR=verwaest@chromium.org,marja@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=

Committed: https://crrev.com/43503288e33dfcc15ab732e4a373e672ecddeb63
Cr-Commit-Position: refs/heads/master@{#39728}

[Michael Hablich, 2016-09-26 14:01:33]

The CQ bit was checked by hablich@chromium.org

[Michael Hablich, 2016-09-26 14:01:34]

Created Reland of VariableProxy: when cloning, don't even think about creating
dangling references.

[commit-bot: I haz the power, 2016-09-26 14:01:36]

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, 2016-09-26 14:01:46]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-09-26 14:02:09]

Description was changed from

==========
Reland of VariableProxy: when cloning, don't even think about creating dangling
references. (patchset #1 id:1 of https://codereview.chromium.org/2368303002/ )

Reason for revert:
wrong CL

Original issue's description:
> Revert of VariableProxy: when cloning, don't even think about creating
dangling references. (patchset #1 id:1 of
https://codereview.chromium.org/2368253002/ )
> 
> Reason for revert:
> Needed for  https://codereview.chromium.org/2373443003/
> 
> Original issue's description:
> > VariableProxy: when cloning, don't even think about creating dangling
references.
> >
> > The code path for cloning resolved VariableProxys (into a different
> > Zone) was never hit, but if it was, it would create a dangling
> > reference, since the Variable would stay in the original Zone.
> >
> > Kudos to verwaest@ for finding this!
> >
> > R=verwaest@chromium.org
> > BUG=
> >
> > Committed: https://crrev.com/fd429bdb9e70cb8c4f8a4bbef0806e008c60440c
> > Cr-Commit-Position: refs/heads/master@{#39723}
> 
> TBR=verwaest@chromium.org,marja@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=
> 
> Committed: https://crrev.com/8edf2905693a2b486a97a0547ec53bb552f7db15
> Cr-Commit-Position: refs/heads/master@{#39726}

TBR=verwaest@chromium.org,marja@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=
==========

to

==========
Reland of VariableProxy: when cloning, don't even think about creating dangling
references. (patchset #1 id:1 of https://codereview.chromium.org/2368303002/ )

Reason for revert:
wrong CL

Original issue's description:
> Revert of VariableProxy: when cloning, don't even think about creating
dangling references. (patchset #1 id:1 of
https://codereview.chromium.org/2368253002/ )
>
> Reason for revert:
> Needed for  https://codereview.chromium.org/2373443003/
>
> Original issue's description:
> > VariableProxy: when cloning, don't even think about creating dangling
references.
> >
> > The code path for cloning resolved VariableProxys (into a different
> > Zone) was never hit, but if it was, it would create a dangling
> > reference, since the Variable would stay in the original Zone.
> >
> > Kudos to verwaest@ for finding this!
> >
> > R=verwaest@chromium.org
> > BUG=
> >
> > Committed: https://crrev.com/fd429bdb9e70cb8c4f8a4bbef0806e008c60440c
> > Cr-Commit-Position: refs/heads/master@{#39723}
>
> TBR=verwaest@chromium.org,marja@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=
>
> Committed: https://crrev.com/8edf2905693a2b486a97a0547ec53bb552f7db15
> Cr-Commit-Position: refs/heads/master@{#39726}

TBR=verwaest@chromium.org,marja@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=

Committed: https://crrev.com/43503288e33dfcc15ab732e4a373e672ecddeb63
Cr-Commit-Position: refs/heads/master@{#39728}
==========

[commit-bot: I haz the power, 2016-09-26 14:02:10]

Patchset 1 (id:??) landed as
https://crrev.com/43503288e33dfcc15ab732e4a373e672ecddeb63
Cr-Commit-Position: refs/heads/master@{#39728}