FrameHostMsg_CreateChildFrame can legitimately fail during renderer shutdown.

FrameHostMsg_CreateChildFrame can legitimately fail during renderer shutdown.

https://crbug.com/631600 shows a legitimate scenario where the browser
destroys WebContents (and consequently RenderProcessHost), but the
renderer process keeps running for a while and calls
RenderFrameImpl::createChildFrame.  In this case we expect to fail
sending FrameHostMsg_CreateChildFrame IPC and therefore to exit early
via:
  if (child_routing_id == MSG_ROUTING_NONE)
      return nullptr;

BUG=631600
Committed: https://crrev.com/c4df88364164c2b0bf8eda3d16a50da716f308e0
Cr-Commit-Position: refs/heads/master@{#408136}

[Łukasz Anforowicz, 2016-07-26 21:28:25]

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

[Łukasz Anforowicz, 2016-07-26 21:28:26]

Charlie, can you take a look please?

[Charlie Reis, 2016-07-26 23:38:00]

[CC dcheng]

Yes, looks like this sync IPC can fail any time the RenderFrameMessageFilter is
gone, which could happen if the tab has been closed as well as prerender.

Looks like we already handle the null case, so making it official seems fine to
me.  LGTM.

[dcheng, 2016-07-27 01:08:57]

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

[dcheng, 2016-07-27 01:08:58]

LGTM (though I think it's slightly surprising that this is the order of events)

[Łukasz Anforowicz, 2016-07-27 15:04:10]

The CQ bit was checked by lukasza@chromium.org

[commit-bot: I haz the power, 2016-07-27 15:04:26]

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, 2016-07-27 15:41:09]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-07-27 15:42:28]

Description was changed from

==========
FrameHostMsg_CreateChildFrame can legitimately fail during renderer shutdown.

https://crbug.com/631600 shows a legitimate scenario where the browser
destroys WebContents (and consequently RenderProcessHost), but the
renderer process keeps running for a while and calls
RenderFrameImpl::createChildFrame.  In this case we expect to fail
sending FrameHostMsg_CreateChildFrame IPC and therefore to exit early
via:
  if (child_routing_id == MSG_ROUTING_NONE)
      return nullptr;

BUG=631600
==========

to

==========
FrameHostMsg_CreateChildFrame can legitimately fail during renderer shutdown.

https://crbug.com/631600 shows a legitimate scenario where the browser
destroys WebContents (and consequently RenderProcessHost), but the
renderer process keeps running for a while and calls
RenderFrameImpl::createChildFrame.  In this case we expect to fail
sending FrameHostMsg_CreateChildFrame IPC and therefore to exit early
via:
  if (child_routing_id == MSG_ROUTING_NONE)
      return nullptr;

BUG=631600

Committed: https://crrev.com/c4df88364164c2b0bf8eda3d16a50da716f308e0
Cr-Commit-Position: refs/heads/master@{#408136}
==========

[commit-bot: I haz the power, 2016-07-27 15:42:29]

Patchset 1 (id:??) landed as
https://crrev.com/c4df88364164c2b0bf8eda3d16a50da716f308e0
Cr-Commit-Position: refs/heads/master@{#408136}