Prevent thread creation if Join has already been called....

Prevent thread creation if Join has already been called.

Tracking the thread id in the constructor, destructor and Start()
shows that the thread object can be started and stopped on
different threads.  This means that there is a race condition
if Stop() or Join() gets called during Start(), which could cause
the thread to start with a pointer to a deleted object.

BUG=23251
TEST=none


Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=29356

[chron_chromium.org, 2009-10-16 18:57:52]

Test?
And add a note about why this is necessary.

[zork, 2009-10-16 21:40:01]

The description has been updated to better explain it.  There's no test
because I don't have a way to reliably reproduce the race condition.

On Fri, Oct 16, 2009 at 11:57 AM, <chron@chromium.org> wrote:

> Test?
> And add a note about why this is necessary.
>
>
> http://codereview.chromium.org/274079
>

[chron_chromium.org, 2009-10-16 23:31:50]

LGTM, but I wish we had a test for this.

On Fri, Oct 16, 2009 at 2:39 PM, Zach Kuznia <zork@google.com> wrote:
> The description has been updated to better explain it. =A0There's no test
> because I don't have a way to reliably reproduce the race condition.
>
> On Fri, Oct 16, 2009 at 11:57 AM, <chron@chromium.org> wrote:
>>
>> Test?
>> And add a note about why this is necessary.
>>
>> http://codereview.chromium.org/274079
>
>



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