Fix crashers and issues when rendering blimp in tabs

Fix crashers and issues when rendering blimp in tabs

- Remove the limitation where size messages was never re-sent if the
  values did not change. However, when creating new BlimpContents, we
  need to re-send the size to get the engine to know the correct size.
- Do a graceful bail out for when BlimpContents are not created. This
  is required when there already is a BlimpContents created, but not
  yet destroyed. This makes WebContents-based and BlimpContents based
  tabs seamless.
- Messages from the engine might arrive after a BlimpContents has been
  deleted, so those messages should be ignored.

BUG=644440
Committed: https://crrev.com/9189c7232659395664e5fc99c62853abd9ffa061
Cr-Commit-Position: refs/heads/master@{#416880}

[nyquist, 2016-09-06 23:02:28]

Description was changed from

==========
Fix a few crashers

BUG=644440
==========

to

==========
Fix crashers and issues when rendering blimp in tabs

- Remove the limitation where size message could only be sent once.
- Do a graceful bail out for when BlimpContents are not created. This is
required when there already is a BlimpContents created, but not yet destroyed.
- Messages from the engine might arrive after a BlimpContents has been deleted,
so those messages should be ignored.

BUG=644440
==========

[nyquist, 2016-09-06 23:04:04]

Description was changed from

==========
Fix crashers and issues when rendering blimp in tabs

- Remove the limitation where size message could only be sent once.
- Do a graceful bail out for when BlimpContents are not created. This is
required when there already is a BlimpContents created, but not yet destroyed.
- Messages from the engine might arrive after a BlimpContents has been deleted,
so those messages should be ignored.

BUG=644440
==========

to

==========
Fix crashers and issues when rendering blimp in tabs

- Remove the limitation where size messages was never re-sent if the
  values did not change. However, when creating new BlimpContents, we
  need to re-send the size to get the engine to know the correct size.
- Do a graceful bail out for when BlimpContents are not created. This
  is required when there already is a BlimpContents created, but not
  yet destroyed. This makes WebContents-based and BlimpContents based
  tabs seamless.
- Messages from the engine might arrive after a BlimpContents has been
  deleted, so those messages should be ignored.

BUG=644440
==========

[nyquist, 2016-09-06 23:04:21]

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

[nyquist, 2016-09-06 23:04:39]

nyquist@chromium.org changed reviewers:
+ dtrainor@chromium.org

[nyquist, 2016-09-06 23:04:39]

dtrainor: PTAL

[commit-bot: I haz the power, 2016-09-06 23:05:32]

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, 2016-09-06 23:51:28]

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

[commit-bot: I haz the power, 2016-09-06 23:51:29]

Dry run: This issue passed the CQ dry run.

[David Trainor- moved to gerrit, 2016-09-07 05:10:30]

lgtm

[nyquist, 2016-09-07 08:03:12]

The CQ bit was checked by nyquist@chromium.org

[commit-bot: I haz the power, 2016-09-07 08:03:25]

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, 2016-09-07 08:07:20]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-09-07 08:08:43]

Description was changed from

==========
Fix crashers and issues when rendering blimp in tabs

- Remove the limitation where size messages was never re-sent if the
  values did not change. However, when creating new BlimpContents, we
  need to re-send the size to get the engine to know the correct size.
- Do a graceful bail out for when BlimpContents are not created. This
  is required when there already is a BlimpContents created, but not
  yet destroyed. This makes WebContents-based and BlimpContents based
  tabs seamless.
- Messages from the engine might arrive after a BlimpContents has been
  deleted, so those messages should be ignored.

BUG=644440
==========

to

==========
Fix crashers and issues when rendering blimp in tabs

- Remove the limitation where size messages was never re-sent if the
  values did not change. However, when creating new BlimpContents, we
  need to re-send the size to get the engine to know the correct size.
- Do a graceful bail out for when BlimpContents are not created. This
  is required when there already is a BlimpContents created, but not
  yet destroyed. This makes WebContents-based and BlimpContents based
  tabs seamless.
- Messages from the engine might arrive after a BlimpContents has been
  deleted, so those messages should be ignored.

BUG=644440

Committed: https://crrev.com/9189c7232659395664e5fc99c62853abd9ffa061
Cr-Commit-Position: refs/heads/master@{#416880}
==========

[commit-bot: I haz the power, 2016-09-07 08:08:47]

Patchset 1 (id:??) landed as
https://crrev.com/9189c7232659395664e5fc99c62853abd9ffa061
Cr-Commit-Position: refs/heads/master@{#416880}