[apps] Add an battery icon to indicate that the battery is charging

Change-Id: I26c616cc6e39f87d305b7bd0c27433e646d74b05

apps/title_bar_view.h

@@ -11,6 +11,7 @@ public:
   void drawRect(KDContext * ctx, KDRect rect) const override;
   void setTitle(I18n::Message title);
   void setChargeState(Ion::Battery::Charge chargeState);
+  void setIsCharging(bool isCharging);
   void refreshPreferences();
 private:
   constexpr static KDCoordinate k_batteryLeftMargin = 5;