customtabs: Don't always destroy the spare WebContents before prerender.

customtabs: Don't always destroy the spare WebContents before prerender.

No longer destroy the spare WebContents in the following cases:
- Prerender is requested but doesn't start. This is the case for 99% of
  stable users as of M58. In this case, don't penalize users.
- Forced prerenders. They are often discarded, and take a small amount
  of memory. In this case, the spare renderer is highly likely to be
  used later.

BUG=728540
Review-Url: https://codereview.chromium.org/2919433005
Cr-Commit-Position: refs/heads/master@{#476615}
Committed: https://chromium.googlesource.com/chromium/src/+/335cbdf575424fa4c2ae627f8b2221df670f4a52

[Benoit L, 2017-06-01 16:12:31]

The CQ bit was checked by lizeb@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-06-01 16:12:56]

Dry run: 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, 2017-06-01 16:57:54]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-06-01 16:57:55]

Dry run: This issue passed the CQ dry run.

[Benoit L, 2017-06-01 17:31:18]

lizeb@chromium.org changed reviewers:
+ yusufo@chromium.org

[Benoit L, 2017-06-01 17:31:23]

The CQ bit was checked by lizeb@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-06-01 17:31:50]

Dry run: 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, 2017-06-01 18:17:49]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-06-01 18:17:49]

Dry run: This issue passed the CQ dry run.

[Yusuf, 2017-06-01 21:07:03]

lgtm

[Benoit L, 2017-06-02 09:16:14]

The CQ bit was checked by lizeb@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-06-02 09:16:29]

Dry run: 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, 2017-06-02 10:02:00]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-06-02 10:02:02]

Dry run: This issue passed the CQ dry run.

[Benoit L, 2017-06-02 10:44:28]

The CQ bit was checked by lizeb@chromium.org

[Benoit L, 2017-06-02 10:44:29]

The patchset sent to the CQ was uploaded after l-g-t-m from yusufo@chromium.org
Link to the patchset: https://codereview.chromium.org/2919433005/#ps40001
(title: "Add a test/")

[commit-bot: I haz the power, 2017-06-02 10:44:45]

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, 2017-06-02 10:49:02]

CQ is committing da patch.

Bot data: {"patchset_id": 40001, "attempt_start_ts": 1496400268995910,
"parent_rev": "c9ad960e2f22c27c7a984ec5bdb14c612737c5ad", "commit_rev":
"335cbdf575424fa4c2ae627f8b2221df670f4a52"}

[commit-bot: I haz the power, 2017-06-02 10:49:09]

Description was changed from

==========
customtabs: Don't always destroy the spare WebContents before prerender.

No longer destroy the spare WebContents in the following cases:
- Prerender is requested but doesn't start. This is the case for 99% of
  stable users as of M58. In this case, don't penalize users.
- Forced prerenders. They are often discarded, and take a small amount
  of memory. In this case, the spare renderer is highly likely to be
  used later.

BUG=728540
==========

to

==========
customtabs: Don't always destroy the spare WebContents before prerender.

No longer destroy the spare WebContents in the following cases:
- Prerender is requested but doesn't start. This is the case for 99% of
  stable users as of M58. In this case, don't penalize users.
- Forced prerenders. They are often discarded, and take a small amount
  of memory. In this case, the spare renderer is highly likely to be
  used later.

BUG=728540

Review-Url: https://codereview.chromium.org/2919433005
Cr-Commit-Position: refs/heads/master@{#476615}
Committed:
https://chromium.googlesource.com/chromium/src/+/335cbdf575424fa4c2ae627f8b22...
==========

[commit-bot: I haz the power, 2017-06-02 10:49:10]

Committed patchset #3 (id:40001) as
https://chromium.googlesource.com/chromium/src/+/335cbdf575424fa4c2ae627f8b22...