Browser Crash when opening urls with NEW_BACKGROUND_TAB disposition...

Browser Crash when opening urls with NEW_BACKGROUND_TAB disposition

When that disposition is used and no "normal" window is opened, it crashes.
"normal" means non POPUP, non APPLICATION window type. This happens because
background disposition doens't focus or activate the window unless selected. A
crash happens because GetSelectedTabContents() is null since nothing initially
there.

This fix might have stopped it crash, but would be best to see if its a "good"
approach.

I fixed some lints such as, header file already exists, extra white space, etc)
BUG=10591
( http://crbug.com/10591 )

Original patch by Mohamed Mansour (see http://codereview.chromium.org/67205/show), r=me,pkasting

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=14288