Update Settings to use themed Context.getDrawable()

Explicit null theme is passed when using Resources.getDrawable() and
no theme is available, e.g. when using getResourcesForApplication().
This fixes an issue with ic_text_dot theming and helps avoid similar
issues in the future.

BUG: 17648301
Change-Id: I3e97c3490b6f2a55744f567b21284f2935ae9af7

src/com/android/settings/fuelgauge/PowerUsageDetail.java

@@ -379,7 +379,7 @@ public class PowerUsageDetail extends Fragment implements Button.OnClickListener
                 // Use default icon
             }
         } else if (iconId != 0) {
-            mAppIcon = getActivity().getResources().getDrawable(iconId);
+            mAppIcon = getActivity().getDrawable(iconId);
         }
         if (mAppIcon == null) {
             mAppIcon = getActivity().getPackageManager().getDefaultActivityIcon();