Fix handle_watcher when start is called twice on the same handle.

Fix handle_watcher when start is called twice on the same handle.

R=viettrungluu@chromium.org

Committed: https://chromium.googlesource.com/external/mojo/+/336dd6af4733ac48a9b68ab97062fb8182a198ed

[qsr, 2014-12-08 13:39:01]

gentle ping?

[viettrungluu, 2014-12-08 18:10:01]

Not super happy about this, but I'm not sure it's worth removing the
apparently-non-trivial work in the dtors, so LGTM.

https://codereview.chromium.org/781753004/diff/1/mojo/common/handle_watcher.cc
File mojo/common/handle_watcher.cc (right):

https://codereview.chromium.org/781753004/diff/1/mojo/common/handle_watcher.c...
mojo/common/handle_watcher.cc:462: state_.reset();
I assume that this is because we need the dtor of the old state to run before
the ctor for the new state (for at least one of
Same/SecondaryThreadWatchingState).

This is pretty unintuitive though, and mostly speaks to the badness of doing
stuff in dtors.

[qsr, 2014-12-09 10:02:23]

https://codereview.chromium.org/781753004/diff/1/mojo/common/handle_watcher.cc
File mojo/common/handle_watcher.cc (right):

https://codereview.chromium.org/781753004/diff/1/mojo/common/handle_watcher.c...
mojo/common/handle_watcher.cc:462: state_.reset();
On 2014/12/08 18:10:01, viettrungluu wrote:
> I assume that this is because we need the dtor of the old state to run before
> the ctor for the new state (for at least one of
> Same/SecondaryThreadWatchingState).
> 
> This is pretty unintuitive though, and mostly speaks to the badness of doing
> stuff in dtors.

 The destructor remove the handler, and neither of those can watch the same
handle multiple times.

[qsr, 2014-12-09 10:02:23]

Committed patchset #1 (id:1) manually as
336dd6af4733ac48a9b68ab97062fb8182a198ed (presubmit successful).