Add ChromeBrowserMainExtraParts for non main parts. (take 3)

Add ChromeBrowserMainExtraParts for non main parts. (take 3)

This was originally submitted as http://codereview.chromium.org/8539038/ which was reverted because of a failing test on win. 

This reverts the code back to a single instance of BrowserMainParts, with auxillary parts (Gtk, Views, Aura, Touch) implemented from a new base class, ChromeBrowserParts, which has a Chrome specific interface, allowing initialization to be better subdivided. 

This should fix the notifications auto tests. 

This CL also addresses the test failure on win (and a test failure on linux_chromeos triggered by the windows fix). 


BUG=103821
TEST=Make sure all tests and autotests run 

TBR=jam@chromium.org

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=110972

[stevenjb, 2011-11-21 17:05:03]

Same as http://codereview.chromium.org/8598005/, without the change to
DesktopNotificationServiceFactory::BuildServiceInstanceFor().

[jam, 2011-11-21 18:28:31]

rubberstamp lgtm