Implement the spring charger replacement UI.

ash/system/chromeos/power/tray_power.h

Index: ash/system/chromeos/power/tray_power.h
diff --git a/ash/system/chromeos/power/tray_power.h b/ash/system/chromeos/power/tray_power.h
index 9fb65b716918a092b20bf6d372d939f32b2b6114..d79ac5e400df413d4d81b634cb580c0ee5dcde34 100644
--- a/ash/system/chromeos/power/tray_power.h
+++ b/ash/system/chromeos/power/tray_power.h
@@ -58,6 +58,17 @@ class ASH_EXPORT TrayPower : public SystemTrayItem,
  private:
   friend class TrayPowerTest;
 
+  // This enum is used for histogram. The existing values should not be removed,
+  // and the new values should be added just before CHARGER_TYPE_COUNT.
+  enum ChargerType{
+    UNKNOWN_CHARGER,
+    MAINS_CHARGER,
+    USB_CHARGER,
+    UNCONFIRMED_SPRING_CHARGER,
+    SAFE_SPRING_CHARGER,
+    CHARGER_TYPE_COUNT,
+  };
+
   // Overridden from SystemTrayItem.
   virtual views::View* CreateTrayView(user::LoginStatus status) OVERRIDE;
   virtual views::View* CreateDefaultView(user::LoginStatus status) OVERRIDE;
@@ -82,6 +93,9 @@ class ASH_EXPORT TrayPower : public SystemTrayItem,
   bool UpdateNotificationStateForRemainingTime();
   bool UpdateNotificationStateForRemainingPercentage();
 
+  // Records the charger type in UMA.
+  void RecordChargerType();
+
   message_center::MessageCenter* message_center_;  // Not owned.
   tray::PowerTrayView* power_tray_;
   tray::PowerNotificationView* notification_view_;
@@ -91,6 +105,9 @@ class ASH_EXPORT TrayPower : public SystemTrayItem,
   // called?
   bool usb_charger_was_connected_;
 
+  // Was line power connected the last time onPowerStatusChanged() was called?
+  bool line_power_was_connected_;
+
   DISALLOW_COPY_AND_ASSIGN(TrayPower);
 };