Fix a crash when closing an incognito window

Fix a crash when closing an incognito window with a download
shelf visible.

We explicitly remove the download shelf view from the browser
view hierarchy during a window close operation. This avoids
calling back into the partially deleted view hierarchy with
download deleted observer notifications. Explicitly removing
the shelf allows the observer notifications to run first while
the views are still valid.


To reproduce:
1. Launch Chrome
2. Open an incognito window
3. Download something in the incognito window
4. The download shelf should become visible with one entry
5. Close the incognito window
6. Crash

BUG=13681
(http://crbug.com/13681)


Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=18458

[Mohamed Mansour, 2009-06-13 04:18:03]

This "now" seems not to crash (unlike the other patch). so LGTM I tried it 3
times.

[Nico, 2009-06-13 04:23:39]

You can get rid of the `browser_ == NULL` check in SetDownloadShelfVisible()
now.

[Ben Goodger (Google), 2009-06-15 20:37:59]

http://codereview.chromium.org/126082/diff/1003/1004
File chrome/browser/views/frame/browser_view.cc (right):

http://codereview.chromium.org/126082/diff/1003/1004#newcode857
Line 857: download_shelf_ = new DownloadShelfView(browser_.get(), this);
download_shelf_ should be a scoped_ptr.
also, when it is created, the following line should be added:

download_shelf_->SetParentOwned(false).

This will remove the need to explicitly remove it then delete it in the dtor.

[Paul Godavari, 2009-06-15 21:56:39]

Updated, though we still need to explicitly reset download_shelf_ before
browser_.