Fix null check to avoid RendererDidNavigateSamePage crash.

Fix null check to avoid RendererDidNavigateSamePage crash.

We shouldn't treat a navigation as NAVIGATION_TYPE_SAME_PAGE if
there is no last committed entry.

BUG=640429
TEST=No known repro steps.  Crashes should go away.
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_site_isolation

Committed: https://crrev.com/08557a213c024dbc17f0f8e62aa31e8bae212711
Cr-Commit-Position: refs/heads/master@{#417070}

[Charlie Reis, 2016-09-07 20:16:52]

Description was changed from

==========
Fix null check to avoid RendererDidNavigateSamePage crash.

We shouldn't treat a navigation as NAVIGATION_TYPE_SAME_PAGE if
there is no last committed entry.

BUG=640429
TEST=No known repro steps.  Crashes should go away.
==========

to

==========
Fix null check to avoid RendererDidNavigateSamePage crash.

We shouldn't treat a navigation as NAVIGATION_TYPE_SAME_PAGE if
there is no last committed entry.

BUG=640429
TEST=No known repro steps.  Crashes should go away.
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_site_isolation
==========

[Charlie Reis, 2016-09-07 20:17:37]

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

[commit-bot: I haz the power, 2016-09-07 20:18:03]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[Charlie Reis, 2016-09-07 20:18:04]

creis@chromium.org changed reviewers:
+ nasko@chromium.org

[Charlie Reis, 2016-09-07 20:18:05]

Nasko, can you review this correction to
https://codereview.chromium.org/2273613003/?  Thanks for pointing the crashes
out to me.

[nasko, 2016-09-07 20:19:33]

LGTM

[Charlie Reis, 2016-09-07 20:30:16]

The CQ bit was unchecked by creis@chromium.org

[Charlie Reis, 2016-09-07 20:30:19]

The CQ bit was checked by creis@chromium.org

[commit-bot: I haz the power, 2016-09-07 20:30:43]

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 22:00:29]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-09-07 22:02:47]

Description was changed from

==========
Fix null check to avoid RendererDidNavigateSamePage crash.

We shouldn't treat a navigation as NAVIGATION_TYPE_SAME_PAGE if
there is no last committed entry.

BUG=640429
TEST=No known repro steps.  Crashes should go away.
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_site_isolation
==========

to

==========
Fix null check to avoid RendererDidNavigateSamePage crash.

We shouldn't treat a navigation as NAVIGATION_TYPE_SAME_PAGE if
there is no last committed entry.

BUG=640429
TEST=No known repro steps.  Crashes should go away.
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_site_isolation

Committed: https://crrev.com/08557a213c024dbc17f0f8e62aa31e8bae212711
Cr-Commit-Position: refs/heads/master@{#417070}
==========

[commit-bot: I haz the power, 2016-09-07 22:02:49]

Patchset 1 (id:??) landed as
https://crrev.com/08557a213c024dbc17f0f8e62aa31e8bae212711
Cr-Commit-Position: refs/heads/master@{#417070}