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();
     }

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

@@ -734,7 +734,7 @@ public class PowerUsageSummary extends PreferenceFragment implements Runnable {
                             (PowerGaugePreference) findPreference(
                                     Integer.toString(bs.uidObj.getUid()));
                     if (pgp != null) {
-                        pgp.setIcon(bs.icon);
+                        pgp.setPowerIcon(bs.icon);
                         pgp.setPercent(bs.percent);
                         pgp.setTitle(bs.name);
                     }