Create CompositePainter once for a widget instead of ref count.  There is a issue in adding new composited child after the ref count of painter  became zero.  RefCount::Release does not tell if it's been deleted so it can't remove the painter key from G_OBJECT(widget).  I could have changed RefCounted::Release to return true, but I took this approach because new child will be added  later in most use case (like info bubble), and it's more efficient to keep the painter rather than  creating and deleting each time.
Create CompositePainter once for a widget instead of ref count.
 There is a issue in adding new composited child after the ref count of painter  became zero.
 RefCount::Release does not tell if it's been deleted so it can't remove the painter key from G_OBJECT(widget).
 I could have changed RefCounted::Release to return true, but I took this approach because new child will be added
 later in most use case (like info bubble), and it's more efficient to keep the painter rather than
 creating and deleting each time.

BUG=none
TEST=none

Review URL: http://codereview.chromium.org/2449010

git-svn-id: dd90618784b6a4b323ea0c23a071cb1c9e6f2ac7@48757 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser