StyleSheetContents::clearResolvers should clear ScopedStyleResolvers

StyleSheetContents::clearResolvers should clear ScopedStyleResolvers

This is a fix for crashes in oilpan builds after landing https://codereview.chromium.org/415743005/.

StyleSheetContents::clearResolvers should clear ScopedStyleResolvers as well as normal StyleResolvers.
The original CL (r178795) that introduced ScopedStyleResolver was missing this code,
and it exposed the bug in oilpan builds when we landed r178817.

BUG=340522
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=178840

[haraken, 2014-07-24 12:20:01]

PTAL

[wibling-chromium, 2014-07-24 12:28:45]

lgtm

Nice detective work:)

[haraken, 2014-07-24 12:30:03]

sof@: Are you fine with landing this CL to fix oilpan crashes at the moment?

[sof, 2014-07-24 12:46:07]

On 2014/07/24 12:30:03, haraken wrote:
> sof@: Are you fine with landing this CL to fix oilpan crashes at the moment?

Yes, but might this call be redundant !ENABLE(OILPAN)? i.e., when the
ScopedStyleTree on the StyleResolver is cleared, its dtor will clear out its
ScopedStyleResolvers. Which doesn't happen with Oilpan enabled.

[kochi, 2014-07-24 12:46:40]

lgtm

https://codereview.chromium.org/419513002/diff/1/Source/core/css/StyleSheetCo...
File Source/core/css/StyleSheetContents.cpp (right):

https://codereview.chromium.org/419513002/diff/1/Source/core/css/StyleSheetCo...
Source/core/css/StyleSheetContents.cpp:623:
document->clearScopedStyleResolver();
Probably eventually we should clear the ScopedStyleResolver for document in
StyleEngine.

Looks good for now.

[haraken, 2014-07-24 12:51:31]

On 2014/07/24 12:46:07, sof wrote:
> On 2014/07/24 12:30:03, haraken wrote:
> > sof@: Are you fine with landing this CL to fix oilpan crashes at the moment?
> 
> Yes, but might this call be redundant !ENABLE(OILPAN)? i.e., when the
> ScopedStyleTree on the StyleResolver is cleared, its dtor will clear out its
> ScopedStyleResolvers. Which doesn't happen with Oilpan enabled.

Yes, it's probably redundant.

kochi-san is planning to remove m_authorStyles and clearScopedStyleResolver()
from ScopedStyleTree's destructor. Since I'm not an expert of the style code, I
might want to land this CL for now and let kochi-san to fix the underlying issue
in a follow up.

[haraken, 2014-07-24 12:51:35]

The CQ bit was checked by haraken@chromium.org

[commit-bot: I haz the power, 2014-07-24 12:51:48]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/haraken@chromium.org/419513002/1

[commit-bot: I haz the power, 2014-07-24 14:00:27]

Change committed as 178840