Null check webview() before using it in RenderViewImpl::OnOrientationChange

Null check webview() before using it in RenderViewImpl::OnOrientationChange

This null check is common in RenderViewImpl callbacks, and there are crash
reports to indicate that it's necessary in OnOrientationChange()

BUG=466485
Committed: https://crrev.com/e20ec7cdb825c84c54392f7fa4dca9d2a1c05158
Cr-Commit-Position: refs/heads/master@{#321186}

[Nate Chapin, 2015-03-13 22:06:11]

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

[Nate Chapin, 2015-03-13 22:06:12]

Not sure whether the isWebLocalFrame() check is strictly necessary.

[Charlie Reis, 2015-03-13 22:47:33]

The crash you linked to is in RenderViewImpl::OnResize, not OnOrientationChange.
 Maybe we should have webview() null checks in both?

nit: s/commit/common/ in CL description.

[Nate Chapin, 2015-03-13 22:52:10]

On 2015/03/13 22:47:33, Charlie Reis wrote:
> The crash you linked to is in RenderViewImpl::OnResize, not
OnOrientationChange.
>  Maybe we should have webview() null checks in both?

OnResize() null-checks its own usage of webview(). It then calls
RenderWidget::OnResize(), which calls RenderViewImpl::OnOrientationChange(),
which doesn't null-check. Both of those functions appear to be elided out of the
stack trace, but this is the only way OnResize() can call into
sendOrientationChangeEvent()

> 
> nit: s/commit/common/ in CL description.

Updated description.

[Charlie Reis, 2015-03-18 18:15:14]

Sorry this got buried in my inbox!  LGTM.

On 2015/03/13 22:52:10, Nate Chapin wrote:
> On 2015/03/13 22:47:33, Charlie Reis wrote:
> > The crash you linked to is in RenderViewImpl::OnResize, not
> OnOrientationChange.
> >  Maybe we should have webview() null checks in both?
> 
> OnResize() null-checks its own usage of webview(). It then calls
> RenderWidget::OnResize(), which calls RenderViewImpl::OnOrientationChange(),
> which doesn't null-check. Both of those functions appear to be elided out of
the
> stack trace, but this is the only way OnResize() can call into
> sendOrientationChangeEvent()

Ah, fun.

[Nate Chapin, 2015-03-18 18:15:30]

The CQ bit was checked by japhet@chromium.org

[commit-bot: I haz the power, 2015-03-18 18:16:03]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1006073002/1

[commit-bot: I haz the power, 2015-03-18 19:16:29]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-03-18 19:17:14]

Patchset 1 (id:??) landed as
https://crrev.com/e20ec7cdb825c84c54392f7fa4dca9d2a1c05158
Cr-Commit-Position: refs/heads/master@{#321186}