Check for an active document in WebPluginContainerImpl::windowClipRect

Check for an active document in WebPluginContainerImpl::windowClipRect

This is a speculative fix for crbug.com/459713. The exact cause is not
clear in our crash reports but this change may fix an issue where the
document is being destroyed. A Document's m_frame is only reset
during destruction, after the lifecycle is set to be not active, so
this patch adds a check for isActive. Additionally, this patch will
move the crash location if the node's renderer is null.

BUG=459713
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=190582

[pdr., 2015-02-20 06:39:09]

pdr@chromium.org changed reviewers:
+ eae@chromium.org, esprehn@chromium.org

[eae, 2015-02-20 17:01:06]

LGTM. If this does end up fixing it I would like to see a test.

[eae, 2015-02-20 17:01:08]

The CQ bit was checked by eae@chromium.org

[commit-bot: I haz the power, 2015-02-20 17:02:08]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/944753004/1

[commit-bot: I haz the power, 2015-02-20 21:55:01]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=190582

[pdr., 2015-02-23 03:35:01]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/947873002/ by pdr@chromium.org.

The reason for reverting is: This did not fix the crash but it gave us enough
info to fix this (in a followup)..