chromeos: Add power supply info reading capability

chrome/browser/chromeos/dbus/power_manager_client.h

Index: chrome/browser/chromeos/dbus/power_manager_client.h
diff --git a/chrome/browser/chromeos/dbus/power_manager_client.h b/chrome/browser/chromeos/dbus/power_manager_client.h
index aa670ad18c2b1fe758ebb841aa14663e63ef5940..2058f340372c58c86df331ea72ba118f77730589 100644
--- a/chrome/browser/chromeos/dbus/power_manager_client.h
+++ b/chrome/browser/chromeos/dbus/power_manager_client.h
@@ -19,6 +19,29 @@ class Signal;
 
 namespace chromeos {
 
+// This is the local struct that is used in Chrome.
+struct PowerSupplyStatus {
+  bool line_power_on;
+
+  bool battery_is_present;
+  bool battery_is_full;
+
+  // Time in seconds until the battery is empty or full, 0 for unknown.
+  int64 battery_seconds_to_empty;
+  int64 battery_seconds_to_full;
+
+  double battery_percentage;
+
+  PowerSupplyStatus() : line_power_on(false),
+                        battery_is_present(false),
+                        battery_is_full(false),
+                        battery_seconds_to_empty(0),
+                        battery_seconds_to_full(0),
+                        battery_percentage(0) {}
+
+  const std::string& ToString() const;
+};
+
 // PowerManagerClient is used to communicate with the power manager.
 class PowerManagerClient {
  public:
@@ -28,7 +51,11 @@ class PowerManagerClient {
     // Called when the brightness is changed.
     // |level| is of the range [0, 100].
     // |user_initiated| is true if the action is initiated by the user.
-    virtual void BrightnessChanged(int level, bool user_initiated) = 0;
+    virtual void BrightnessChanged(int level, bool user_initiated) {}
+
+    // Called when power supply polling takes place.  |status| is a data
+    // structure that contains the current state of the power supply.
+    virtual void PowerChanged(const PowerSupplyStatus& status) {}
   };
 
   // Adds and removes the observer.
@@ -42,6 +69,9 @@ class PowerManagerClient {
   // Increases the screen brightness.
   virtual void IncreaseScreenBrightness() = 0;
 
+  // UI initiated request for status update.
+  virtual void RequestStatusUpdate() = 0;
+
   // Creates the instance.
   static PowerManagerClient* Create(dbus::Bus* bus);