Invalidate weak pointer factory in statistics prefs on UI thread.

Invalidate weak pointer factory in statistics prefs on UI thread.

DataReductionProxyStatisticsPrefs is instantiated on UI thread and then
its ownership is passed to IOThread. This causes weak_factory_ to be
invalidated on a different thread from the one it is created on. This
cl explicitly invalidates it on UI Thread.

BUG=428931
Committed: https://crrev.com/e15038f26f1924d24faebba7e764e40439f14254
Cr-Commit-Position: refs/heads/master@{#302175}

[bengr, 2014-10-30 20:32:29]

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

[bengr, 2014-10-30 20:32:30]

https://codereview.chromium.org/669783004/diff/1/components/data_reduction_pr...
File
components/data_reduction_proxy/core/browser/data_reduction_proxy_statistics_prefs.cc
(right):

https://codereview.chromium.org/669783004/diff/1/components/data_reduction_pr...
components/data_reduction_proxy/core/browser/data_reduction_proxy_statistics_prefs.cc:42:
weak_factory_.InvalidateWeakPtrs();
Should this be last? What happen if a pref change comes in after the weak
pointers have been invalidated?

Please add a comment that explains the rationale for the ordering.

[bengr, 2014-10-30 20:33:53]

lgtm

https://codereview.chromium.org/669783004/diff/1/components/data_reduction_pr...
File
components/data_reduction_proxy/core/browser/data_reduction_proxy_statistics_prefs.cc
(right):

https://codereview.chromium.org/669783004/diff/1/components/data_reduction_pr...
components/data_reduction_proxy/core/browser/data_reduction_proxy_statistics_prefs.cc:42:
weak_factory_.InvalidateWeakPtrs();
On 2014/10/30 20:32:29, bengr wrote:
> Should this be last? What happen if a pref change comes in after the weak
> pointers have been invalidated?
> 
> Please add a comment that explains the rationale for the ordering.

I guess it doesn't really matter, right, because this is all happening on the
same thread.

[Not at Google. Contact bengr, 2014-10-30 20:51:33]

https://codereview.chromium.org/669783004/diff/1/components/data_reduction_pr...
File
components/data_reduction_proxy/core/browser/data_reduction_proxy_statistics_prefs.cc
(right):

https://codereview.chromium.org/669783004/diff/1/components/data_reduction_pr...
components/data_reduction_proxy/core/browser/data_reduction_proxy_statistics_prefs.cc:42:
weak_factory_.InvalidateWeakPtrs();
On 2014/10/30 20:33:53, bengr wrote:
> On 2014/10/30 20:32:29, bengr wrote:
> > Should this be last? What happen if a pref change comes in after the weak
> > pointers have been invalidated?
> > 
> > Please add a comment that explains the rationale for the ordering.
> 
> I guess it doesn't really matter, right, because this is all happening on the
> same thread.

Yeah, shouldnt matter unless weak_factory_ gets used on IOThread which it should
not be.

[Not at Google. Contact bengr, 2014-10-30 21:57:16]

The CQ bit was checked by kundaji@chromium.org

[commit-bot: I haz the power, 2014-10-30 21:57:45]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/669783004/40001

[commit-bot: I haz the power, 2014-10-30 22:39:00]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2014-10-30 22:39:34]

Patchset 3 (id:??) landed as
https://crrev.com/e15038f26f1924d24faebba7e764e40439f14254
Cr-Commit-Position: refs/heads/master@{#302175}