Revert of android: Switch CleanupReference to PhantomReference

Revert of android: Switch CleanupReference to PhantomReference (patchset #1 id:1 of https://codereview.chromium.org/2241533002/ )

Reason for revert:
Experiment out. Reverting. See bug for reasoning.

Original issue's description:
> android: Switch CleanupReference to PhantomReference
>
> Again. This time due to correctness. Want to experiment on beta to see
> how big the impact is. Quoting from the comment in the CL:
>
> NOTE Using PhantonReference instead of WeakReference is required for correctness.
> WeakReferences are enqueued before finalizers are called, and finalizers can
> resurrect the referent object. PhantomReference does delay clean up more compared
> to WeakReference.
>
> BUG=618807
>
> Committed: https://crrev.com/630d88124d2e5a3fda6b9fd25d06eaa1af403fca
> Cr-Commit-Position: refs/heads/master@{#411417}

TBR=dtrainor@chromium.org,yfriedman@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=618807
Committed: https://crrev.com/74e50f4c229d7b9f895a3108abdd0309395b919c
Cr-Commit-Position: refs/heads/master@{#412871}

[boliu, 2016-08-18 16:47:04]

The CQ bit was checked by boliu@chromium.org

[boliu, 2016-08-18 16:47:04]

Created Revert of android: Switch CleanupReference to PhantomReference

[commit-bot: I haz the power, 2016-08-18 16:47:25]

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, 2016-08-18 17:28:32]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-08-18 17:30:43]

Description was changed from

==========
Revert of android: Switch CleanupReference to PhantomReference (patchset #1 id:1
of https://codereview.chromium.org/2241533002/ )

Reason for revert:
Experiment out. Reverting. See bug for reasoning.

Original issue's description:
> android: Switch CleanupReference to PhantomReference
> 
> Again. This time due to correctness. Want to experiment on beta to see
> how big the impact is. Quoting from the comment in the CL:
> 
> NOTE Using PhantonReference instead of WeakReference is required for
correctness.
> WeakReferences are enqueued before finalizers are called, and finalizers can
> resurrect the referent object. PhantomReference does delay clean up more
compared
> to WeakReference.
> 
> BUG=618807
> 
> Committed: https://crrev.com/630d88124d2e5a3fda6b9fd25d06eaa1af403fca
> Cr-Commit-Position: refs/heads/master@{#411417}

TBR=dtrainor@chromium.org,yfriedman@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=618807
==========

to

==========
Revert of android: Switch CleanupReference to PhantomReference (patchset #1 id:1
of https://codereview.chromium.org/2241533002/ )

Reason for revert:
Experiment out. Reverting. See bug for reasoning.

Original issue's description:
> android: Switch CleanupReference to PhantomReference
>
> Again. This time due to correctness. Want to experiment on beta to see
> how big the impact is. Quoting from the comment in the CL:
>
> NOTE Using PhantonReference instead of WeakReference is required for
correctness.
> WeakReferences are enqueued before finalizers are called, and finalizers can
> resurrect the referent object. PhantomReference does delay clean up more
compared
> to WeakReference.
>
> BUG=618807
>
> Committed: https://crrev.com/630d88124d2e5a3fda6b9fd25d06eaa1af403fca
> Cr-Commit-Position: refs/heads/master@{#411417}

TBR=dtrainor@chromium.org,yfriedman@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=618807

Committed: https://crrev.com/74e50f4c229d7b9f895a3108abdd0309395b919c
Cr-Commit-Position: refs/heads/master@{#412871}
==========

[commit-bot: I haz the power, 2016-08-18 17:30:44]

Patchset 1 (id:??) landed as
https://crrev.com/74e50f4c229d7b9f895a3108abdd0309395b919c
Cr-Commit-Position: refs/heads/master@{#412871}