Fix a bug where we would show both the apps and thumb sections

chrome/browser/dom_ui/shown_sections_handler.h

Index: chrome/browser/dom_ui/shown_sections_handler.h
diff --git a/chrome/browser/dom_ui/shown_sections_handler.h b/chrome/browser/dom_ui/shown_sections_handler.h
index 8821d6407b29cf7ffcb6b9edc3f8e576c736c3ac..14a32151bf85d0bf5e1d0bce3d059a0ea1d056be 100644
--- a/chrome/browser/dom_ui/shown_sections_handler.h
+++ b/chrome/browser/dom_ui/shown_sections_handler.h
@@ -14,13 +14,10 @@ class Value;
 class PrefService;
 
 // Use for the shown sections bitmask.
+// Currently, only the THUMB and APPS sections can be toggled by the user. Other
+// sections are shown automatically if they have data, and hidden otherwise.
 enum Section {
   THUMB = 1,
-  LIST = 2,
-  RECENT = 4,
-  TIPS = 8,
-  SYNC = 16,
-  DEBUG = 32,
   APPS = 64
 };