ObserverList::HasObserver now takes a const pointer.

chromeos/dbus/power_manager_client.cc

Index: chromeos/dbus/power_manager_client.cc
diff --git a/chromeos/dbus/power_manager_client.cc b/chromeos/dbus/power_manager_client.cc
index b2e8416f996842d531032eeafd5cd2a00c3cc8fe..4192e0d143fdc891b9f9784b356194d6fdddbb11 100644
--- a/chromeos/dbus/power_manager_client.cc
+++ b/chromeos/dbus/power_manager_client.cc
@@ -78,7 +78,7 @@ class PowerManagerClientImpl : public PowerManagerClient {
     observers_.RemoveObserver(observer);
   }
 
-  virtual bool HasObserver(Observer* observer) override {
+  virtual bool HasObserver(const Observer* observer) const override {
     return observers_.HasObserver(observer);
   }
 
@@ -780,7 +780,7 @@ class PowerManagerClientStubImpl : public PowerManagerClient {
     observers_.RemoveObserver(observer);
   }
 
-  virtual bool HasObserver(Observer* observer) override {
+  virtual bool HasObserver(const Observer* observer) const override {
     return observers_.HasObserver(observer);
   }