Fix scoped_refptr assignment operator in the case of having it as a member.

Fix scoped_refptr assignment operator in the case of having it as a member.

If a class holds a reference to itself in scoped_refptr, assigning
to it a new value leads to calling Release while in destructor.

R=levin@chromium.org
TEST=RefCountedUnitTest.ScopedRefPtrToSelf

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=116480

[mnaganov (inactive), 2011-12-21 15:50:09]

Marc-Antoine, I see that David is OOO, adding you.

[M-A Ruel, 2011-12-21 15:56:36]

lgtm

[joth, 2011-12-21 16:51:27]

drive by :)

http://codereview.chromium.org/9021020/diff/1/base/memory/ref_counted.h
File base/memory/ref_counted.h (right):

http://codereview.chromium.org/9021020/diff/1/base/memory/ref_counted.h#newco...
base/memory/ref_counted.h:269: }
Maybe marginally easier to read as..

T* old_ptr = ptr_;
ptr_ = p;
if (old_ptr)
  old_ptr->Release();

(and there's an outside change that would optimize better on ARM too)

[mnaganov (inactive), 2011-12-21 17:02:53]

Indeed, thanks! :)

I had a feeling there must be something wrong with the assignment statement
duplication.

[joth, 2011-12-22 17:09:06]

lgtm

[mnaganov (inactive), 2011-12-28 09:35:32]

Darin, I need owner's approval. Can you please take a look?

[darin (slow to review), 2012-01-03 20:16:32]

LGTM (I'm surprised we've gotten this far without having to make this change.)