Should only create one downloads tab per window. Introducing another window disposition

Should only create one downloads tab per window. If there is already a Downloads tab, then switch to it instead of creating new one. This would be similar to the way Ctrl+J works.

As well, a FOCUS_SINGLETON_TAB disposition was implemented in which is a great  feature to have, in case we would like to just open one tab.

BUG=8767
( http://crbug.com/8767 )

[Mohamed Mansour (USE mhm), 2009-03-19 06:28:13]

New build (using latest svn)

[Evan Stade, 2009-03-19 18:32:00]

CCed Ben.

LGTM. Could you delete the second paragraph of the change description?

http://codereview.chromium.org/50003/diff/1/5
File webkit/glue/window_open_disposition.h (right):

http://codereview.chromium.org/50003/diff/1/5#newcode21
Line 21: #endif  // WEBKIT_GLUE_WINDOW_OPEN_DISPOSITION_H__
while you're here, can you fix the trailing underscores on this guard? (should
only be 1)

[Mohamed Mansour (USE mhm), 2009-03-19 18:36:46]

On 2009/03/19 18:32:00, estade wrote:
> CCed Ben.
> 
> LGTM. Could you delete the second paragraph of the change description?
> 
done!

> http://codereview.chromium.org/50003/diff/1/5
> File webkit/glue/window_open_disposition.h (right):
> 
> http://codereview.chromium.org/50003/diff/1/5#newcode21
> Line 21: #endif  // WEBKIT_GLUE_WINDOW_OPEN_DISPOSITION_H__
> while you're here, can you fix the trailing underscores on this guard? (should
> only be 1)
done!

[Ben Goodger (Google), 2009-03-22 21:09:58]

+CC pkasting, who was involved in the WindowOpenDisposition stuff and may have
an opinion.

[Peter Kasting, 2009-03-23 00:49:42]

I haven't really been paying attention; my only comment is that "SINGLETON_TAB"
seems like a better name, since really that disposition is intended to mean
"create such a tab if it doesn't exists or else focus it", whereas
FOCUS_SINGLETON_TAB only sounds like it would do the latter.

Other than that, if the behavior is something desirable, doing it via a new
disposition seems like the right thing to me.

[Peter Kasting, 2009-03-23 00:50:37]

Oh, also: Be careful when adding this.  Audit existing code, not just in
browser/ but everywhere (e.g. glue layer).  Make sure no one else needs handlers
added for this, or comments updated.

[Mohamed Mansour (USE mhm), 2009-03-23 05:11:28]

done.

I have checked the glue layer, afaik, the only thing needed is that open
disposition header file.

[Mohamed Mansour (USE mhm), 2009-03-27 21:40:19]

Could someone commit this?

[Evan Stade, 2009-04-02 22:31:07]

committed in r13045