MacViews: support backgrounds for selected rows

ui/views/style/platform_style.h

Index: ui/views/style/platform_style.h
diff --git a/ui/views/style/platform_style.h b/ui/views/style/platform_style.h
index 3a6392622d465819ea9ff14f4357d272a040324d..50cab9c65cfeff753491fd13aa9b23b38f34964a 100644
--- a/ui/views/style/platform_style.h
+++ b/ui/views/style/platform_style.h
@@ -38,6 +38,10 @@ class VIEWS_EXPORT PlatformStyle {
   // the left or right end of the text from the cursor, respectively.
   static const bool kTextfieldDragVerticallyDragsToEnd;
 
+  // Whether selecting a row in a TreeView selects the entire row or only the
+  // label for that row.
+  static const bool kTreeViewSelectsEntireRow;
+
   // Creates an ImageSkia containing the image to use for the combobox arrow.
   // The |is_enabled| argument is true if the control the arrow is for is
   // enabled, and false if the control is disabled. The |style| argument is the