sync: Remove ChangeProcessor::Stop()

sync: Remove ChangeProcessor::Stop()

Stopping the ChangeProcessor from the UI is racy, especially for data
types with controllers that directly extend
NonFrontendDataTypeController.  This can lead to crashes or DCHECK
failures.

It turns out that the easiest way to fix this is to not Stop() the
ChangeProcessors from the UI thread.  There are no data types that
require this functionality.  It is at best unnecessary and at worst
harmful.

Without Stop(), there is no longer any need to check if a
ChangeProcessor is running.  Therefore, running_ and its associated
methods, DCHECKs, etc. have been removed, too.

BUG=151606
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=159600

[rlarocque, 2012-09-28 17:45:40]

I'm mostly convinced this is correct, though I'm not sure I fully understand the
context in which some of this code will be run.

Please review.

[Nicolas Zea, 2012-10-01 16:22:13]

LGTM. Note that themes is now using the syncable service api, so you'll likely
get conflicts on that.

http://codereview.chromium.org/10979067/diff/1/chrome/browser/sync/glue/bookm...
File chrome/browser/sync/glue/bookmark_change_processor.cc (right):

http://codereview.chromium.org/10979067/diff/1/chrome/browser/sync/glue/bookm...
chrome/browser/sync/glue/bookmark_change_processor.cc:51: bookmark_model_ =
NULL;
these two lines aren't needed.

http://codereview.chromium.org/10979067/diff/1/chrome/browser/sync/glue/sessi...
File chrome/browser/sync/glue/session_change_processor.cc (right):

http://codereview.chromium.org/10979067/diff/1/chrome/browser/sync/glue/sessi...
chrome/browser/sync/glue/session_change_processor.cc:84: profile_ = NULL;
not needed

[rlarocque, 2012-10-01 20:00:46]

Updated.  I'll be hitting the commit button soon.

http://codereview.chromium.org/10979067/diff/1/chrome/browser/sync/glue/bookm...
File chrome/browser/sync/glue/bookmark_change_processor.cc (right):

http://codereview.chromium.org/10979067/diff/1/chrome/browser/sync/glue/bookm...
chrome/browser/sync/glue/bookmark_change_processor.cc:51: bookmark_model_ =
NULL;
On 2012/10/01 16:22:13, nzea wrote:
> these two lines aren't needed.

Done.

http://codereview.chromium.org/10979067/diff/1/chrome/browser/sync/glue/sessi...
File chrome/browser/sync/glue/session_change_processor.cc (right):

http://codereview.chromium.org/10979067/diff/1/chrome/browser/sync/glue/sessi...
chrome/browser/sync/glue/session_change_processor.cc:84: profile_ = NULL;
On 2012/10/01 16:22:13, nzea wrote:
> not needed

Done.

[commit-bot: I haz the power, 2012-10-01 20:02:15]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/[email protected]/10979067/13001

[commit-bot: I haz the power, 2012-10-02 00:22:54]

Change committed as 159600