Bug 721354 - Update about:home everytime it's shown (r=blassey)

mobile/android/base/GeckoApp.java

@@ -1114,7 +1114,11 @@ abstract public class GeckoApp
                     new RelativeLayout.LayoutParams(LayoutParams.FILL_PARENT, 
                                                     LayoutParams.FILL_PARENT);
                 mGeckoLayout.addView(mAboutHomeContent, lp);
+            } else if (mAboutHomeContent != null && mShow) {
+                mAboutHomeContent.update(GeckoApp.mAppContext,
+                                         EnumSet.of(AboutHomeContent.UpdateFlags.TOP_SITES));
             }
+
             if (mAboutHomeContent != null)
                 mAboutHomeContent.setVisibility(mShow ? View.VISIBLE : View.GONE);
         }