ObserverList::HasObserver now takes a const pointer.

chromeos/dbus/update_engine_client.cc

Index: chromeos/dbus/update_engine_client.cc
diff --git a/chromeos/dbus/update_engine_client.cc b/chromeos/dbus/update_engine_client.cc
index 6a777b5cfca8906684835c21fe4c571446fa1197..19f3e0634b14fcc82e418da72d29ebf16fa76662 100644
--- a/chromeos/dbus/update_engine_client.cc
+++ b/chromeos/dbus/update_engine_client.cc
@@ -98,7 +98,7 @@ class UpdateEngineClientImpl : public UpdateEngineClient {
     observers_.RemoveObserver(observer);
   }
 
-  virtual bool HasObserver(Observer* observer) override {
+  virtual bool HasObserver(const Observer* observer) const override {
     return observers_.HasObserver(observer);
   }
 
@@ -412,7 +412,9 @@ class UpdateEngineClientStubImpl : public UpdateEngineClient {
   virtual void Init(dbus::Bus* bus) override {}
   virtual void AddObserver(Observer* observer) override {}
   virtual void RemoveObserver(Observer* observer) override {}
-  virtual bool HasObserver(Observer* observer) override { return false; }
+  virtual bool HasObserver(const Observer* observer) const override {
+    return false;
+  }
 
   virtual void RequestUpdateCheck(
       const UpdateCheckCallback& callback) override {
@@ -467,7 +469,7 @@ class UpdateEngineClientFakeImpl : public UpdateEngineClientStubImpl {
       observers_.RemoveObserver(observer);
   }
 
-  virtual bool HasObserver(Observer* observer) override {
+  virtual bool HasObserver(const Observer* observer) const override {
     return observers_.HasObserver(observer);
   }