chromeos: call GetIdleTime from power manager client

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 272d6088cfbe993873c88a60ff0a70df40e65e94..9b4323162e63467c6a8720958ad33f5190c27594 100644
--- a/chrome/browser/chromeos/dbus/power_manager_client.h
+++ b/chrome/browser/chromeos/dbus/power_manager_client.h
@@ -8,6 +8,7 @@
 #include <string>
 
 #include "base/basictypes.h"
+#include "base/callback.h"
 
 namespace dbus {
 class Bus;
@@ -32,6 +33,10 @@ struct PowerSupplyStatus {
   const std::string& ToString() const;
 };
 
+// Callback used for processing the idle time.  The int64 param is the number of
+// seconds the user has been idle.
+typedef base::Callback<void(int64)> CalculateIdleTimeCallback;
+
 // PowerManagerClient is used to communicate with the power manager.
 class PowerManagerClient {
  public:
@@ -68,6 +73,11 @@ class PowerManagerClient {
   // Requests shutdown of the system.
   virtual void RequestShutdown() = 0;
 
+  // Calculates idle time asynchronously, after the idle time request has
+  // replied.  It passes the idle time in seconds to |callback|.  If it
+  // encounters some error, it passes -1 to |callback|.
+  virtual void CalculateIdleTime(const CalculateIdleTimeCallback& callback) = 0;
+
   // Creates the instance.
   static PowerManagerClient* Create(dbus::Bus* bus);