[Sync] Fix double tranaction acquire in favicon code

[Sync] Fix double tranaction acquire in favicon code

FaviconCache::OnReceivedSyncFavicon now posts a task for UpdateSyncState,
due to the possibility that the method is called from within a sync
transaction.

BUG=223400
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=190487

[Nicolas Zea, 2013-03-25 21:09:52]

PTAL

[rlarocque, 2013-03-25 21:30:57]

https://codereview.chromium.org/13006012/diff/1/chrome/browser/sync/glue/favi...
File chrome/browser/sync/glue/favicon_cache_unittest.cc (right):

https://codereview.chromium.org/13006012/diff/1/chrome/browser/sync/glue/favi...
chrome/browser/sync/glue/favicon_cache_unittest.cc:291: MessageLoopForUI
message_loop_;
Is this used anywhere?

[Nicolas Zea, 2013-03-25 21:37:30]

https://codereview.chromium.org/13006012/diff/1/chrome/browser/sync/glue/favi...
File chrome/browser/sync/glue/favicon_cache_unittest.cc (right):

https://codereview.chromium.org/13006012/diff/1/chrome/browser/sync/glue/favi...
chrome/browser/sync/glue/favicon_cache_unittest.cc:291: MessageLoopForUI
message_loop_;
On 2013/03/25 21:30:57, rlarocque wrote:
> Is this used anywhere?

It's necessary so that MessageLoop::current() doesn't return null.

[rlarocque, 2013-03-25 21:38:19]

On 2013/03/25 21:37:30, Nicolas Zea wrote:
>
https://codereview.chromium.org/13006012/diff/1/chrome/browser/sync/glue/favi...
> File chrome/browser/sync/glue/favicon_cache_unittest.cc (right):
> 
>
https://codereview.chromium.org/13006012/diff/1/chrome/browser/sync/glue/favi...
> chrome/browser/sync/glue/favicon_cache_unittest.cc:291: MessageLoopForUI
> message_loop_;
> On 2013/03/25 21:30:57, rlarocque wrote:
> > Is this used anywhere?
> 
> It's necessary so that MessageLoop::current() doesn't return null.

Ah, OK.  LGTM.

[Nicolas Zea, 2013-03-25 21:53:17]

Committed patchset #1 manually as r190487 (presubmit successful).