chromeos: Add power supply info reading capability

chrome/browser/chromeos/cros/power_library.h

Index: chrome/browser/chromeos/cros/power_library.h
diff --git a/chrome/browser/chromeos/cros/power_library.h b/chrome/browser/chromeos/cros/power_library.h
index 10f99f5b43bc1e2377fd1b7bf10cbbd405215cb7..3b152de49242e5ada6789c15fdcb898d184364e3 100644
--- a/chrome/browser/chromeos/cros/power_library.h
+++ b/chrome/browser/chromeos/cros/power_library.h
@@ -6,7 +6,10 @@
 #define CHROME_BROWSER_CHROMEOS_CROS_POWER_LIBRARY_H_
 #pragma once
 
+// TODO(sque): Move to chrome/browser/chromeos/system, crosbug.com/16558
+
 #include "base/callback.h"
+#include "chrome/browser/chromeos/dbus/power_manager_client.h"
 
 namespace base {
 class TimeDelta;
@@ -15,11 +18,12 @@ class TimeDelta;
 namespace chromeos {
 
 typedef base::Callback<void(int64_t)> CalculateIdleTimeCallback;
+struct PowerStatus;
 
 // This interface defines interaction with the ChromeOS power library APIs.
 // Classes can add themselves as observers. Users can get an instance of this
 // library class like this: chromeos::CrosLibrary::Get()->GetPowerLibrary()
-class PowerLibrary {
+class PowerLibrary : public PowerManagerClient::Observer {
  public:
   class Observer {
    public:
@@ -71,6 +75,10 @@ class PowerLibrary {
   // UI initiated request for status update.
   virtual void RequestStatusUpdate() = 0;
 
+  // Requests power supply info.
+  virtual void UpdatePowerStatus(const chromeos::PowerStatus& status) = 0;
+
+
   // Factory function, creates a new instance and returns ownership.
   // For normal usage, access the singleton via CrosLibrary::Get().
   static PowerLibrary* GetImpl(bool stub);