More aggressive DCHECKs for FrameTree::setName.

More aggressive DCHECKs for FrameTree::setName.

BUG=618813
Committed: https://crrev.com/543dc5fcb73056046770cf5489ace558811ff20d
Cr-Commit-Position: refs/heads/master@{#400500}

[Łukasz Anforowicz, 2016-06-16 22:11:37]

lukasza@chromium.org changed reviewers:
+ dcheng@chromium.org

[Łukasz Anforowicz, 2016-06-16 22:11:38]

Daniel, can you take a look please?  This is a follow-up to
https://codereview.chromium.org/2053903002/.

PS. I also owe you another follow-up (to move FrameLoaderClient::didChangeName
call into FrameTree::setName) - I am still trying to come up with a browser test
that shows that we missed a didChangeName call in some scenario (and so, the
browser had out-of-date knowledge about frame names).

https://codereview.chromium.org/2078643002/diff/1/third_party/WebKit/Source/c...
File third_party/WebKit/Source/core/page/FrameTree.cpp (right):

https://codereview.chromium.org/2078643002/diff/1/third_party/WebKit/Source/c...
third_party/WebKit/Source/core/page/FrameTree.cpp:65: || (m_uniqueName.isNull()
&& m_name.isNull() && !parent()));
I think it is important to move this DCHECK out of the "if" statement's body.

Before this CL, the DCHECK would fire in case where m_uniqueName is left in a
broken, uninitialized state.

After this CL, the DCHECK will fire in cases where m_uniqueName can
*potentially* be left in a broken, uninitialized state (because
FrameTree::setName was called at a bad time).

[dcheng, 2016-06-17 19:54:57]

lgtm

[Łukasz Anforowicz, 2016-06-17 20:02:55]

The CQ bit was checked by lukasza@chromium.org

[commit-bot: I haz the power, 2016-06-17 20:03:32]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2078643002/1

[commit-bot: I haz the power, 2016-06-17 20:54:22]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-06-17 20:56:07]

Description was changed from

==========
More aggressive DCHECKs for FrameTree::setName.

BUG=618813
==========

to

==========
More aggressive DCHECKs for FrameTree::setName.

BUG=618813

Committed: https://crrev.com/543dc5fcb73056046770cf5489ace558811ff20d
Cr-Commit-Position: refs/heads/master@{#400500}
==========

[commit-bot: I haz the power, 2016-06-17 20:56:08]

Patchset 1 (id:??) landed as
https://crrev.com/543dc5fcb73056046770cf5489ace558811ff20d
Cr-Commit-Position: refs/heads/master@{#400500}