Actually make theme object a singleton

shell/home/FriendsView.py

@@ -5,12 +5,12 @@ import goocanvas
 from sugar.canvas.IconItem import IconItem
 from sugar.canvas.IconItem import IconColor
 
-from Theme import Theme
+import Theme
 
 class Model(goocanvas.CanvasModelSimple):
 	def __init__(self, data_model):
 		goocanvas.CanvasModelSimple.__init__(self)
-		self._theme = Theme()
+		self._theme = Theme.get_instance()
 		self._theme.connect("theme-changed", self.__theme_changed_cb)
 
 		root = self.get_root_item()

shell/home/HomeView.py

@@ -8,7 +8,7 @@ from sugar.canvas.DonutItem import DonutItem
 from sugar.canvas.DonutItem import PieceItem
 from sugar.canvas.DonutItem import PieceIcon
 
-from Theme import Theme
+import Theme
 
 class TasksItem(DonutItem):
 	def __init__(self, shell):
@@ -43,7 +43,7 @@ class TasksItem(DonutItem):
 class Background(goocanvas.Group):
 	def __init__(self):
 		goocanvas.Group.__init__(self)
-		self._theme = Theme()
+		self._theme = Theme.get_instance()
 		self._theme.connect("theme-changed", self.__theme_changed_cb)
 
 		color = self._theme.get_home_colors()[1]

shell/home/Theme.py

@@ -39,3 +39,12 @@ class Theme(gobject.GObject):
 
 	def get_home_colors(self):
 		return self.__colors[self._cur_theme]
+
+
+# Use this accessor, don't create more than one theme object
+_theme = None
+def get_instance():
+	global _theme
+	if not _theme:
+		_theme = Theme()
+	return _theme