Workaround a crash occuring only in v20 and v21 without a repro case (need more data for good fix)

Workaround a crash occuring only in v20 and v21 without a repro case (need more data for good fix)

Spend around 2 days with reproducing the problem, checking out the underlying code, and discussing with others (see bug for more info) without further insights. Since the bug is gone with v22 and we might get more data if it crashes later, we hope that this is an adequate solution for the problem (even though it is not satisfying).


BUG=134465
TEST=NONE and not reproducible


Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=147982

[Mr4D (OOO till 08-26), 2012-07-18 20:52:09]

Hi Ben!

This one is tricky - spent already over two days on it. After discussing with
derat and others we decided that this is a good course of action. If you have
any further ideas - your input is highly welcome. Please have a look at the bug
13446 for more details (I added all I have found out there)!

Many thanks in advance!
-Stefan

[Mr4D (OOO till 08-26), 2012-07-19 14:36:03]

Hi Brett!

Since Ben is on Vacation I'll send this over to you.

This one is tricky - spent already over two days on it. After discussing with
derat and others we decided that this is a good course of action. If you have
any further ideas - your input is highly welcome. Please have a look at the bug
13446 for more details (I added all I have found out there)!

Many thanks in advance!
-Stefan

[brettw, 2012-07-23 17:44:45]

http://codereview.chromium.org/10790058/diff/1/content/browser/renderer_host/...
File content/browser/renderer_host/render_widget_host_impl.cc (right):

http://codereview.chromium.org/10790058/diff/1/content/browser/renderer_host/...
content/browser/renderer_host/render_widget_host_impl.cc:883: // Looking
extensively for over a day, a delegate_ of NULL seems
This comment isn't clear when not in the context of the diff. It's not clear
what the "fix" is that it's referring to. Also, I'm not sure if "looking
extensively for over a day" is necessary.

I'd write something like "A delegate_ of NULL seems impossible but crash reports
show that it can happen (see http://crbug.com/134465). This doesn't seem to
happen in Chrome 22 and later, so checking for the delegate_ here can be removed
once Chrome 22 goes to stable."

[Mr4D (OOO till 08-26), 2012-07-23 21:46:17]

Addressed. Please have another look!

http://codereview.chromium.org/10790058/diff/1/content/browser/renderer_host/...
File content/browser/renderer_host/render_widget_host_impl.cc (right):

http://codereview.chromium.org/10790058/diff/1/content/browser/renderer_host/...
content/browser/renderer_host/render_widget_host_impl.cc:883: // Looking
extensively for over a day, a delegate_ of NULL seems
On 2012/07/23 17:44:45, brettw wrote:
> This comment isn't clear when not in the context of the diff. It's not clear
> what the "fix" is that it's referring to. Also, I'm not sure if "looking
> extensively for over a day" is necessary.
> 
> I'd write something like "A delegate_ of NULL seems impossible but crash
reports
> show that it can happen (see http://crbug.com/134465). This doesn't seem to
> happen in Chrome 22 and later, so checking for the delegate_ here can be
removed
> once Chrome 22 goes to stable."

Done.

[brettw, 2012-07-23 21:49:57]

lgtm

[commit-bot: I haz the power, 2012-07-23 21:50:21]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/skuhne@chromium.org/10790058/5001

[commit-bot: I haz the power, 2012-07-23 23:12:50]

Change committed as 147982