Use the new Preference:icon attribute and placeholder for showing icons on the left.

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

@@ -64,7 +64,7 @@ public class PowerGaugePreference extends Preference {
         return mInfo;
     }
 
-    void setIcon(Drawable icon) {
+    void setPowerIcon(Drawable icon) {
         mIcon = icon;
         notifyChanged();
     }