[GRC] Coordination Unit Graph Observer

services/resource_coordinator/coordination_unit/coordination_unit_impl.h

Index: services/resource_coordinator/coordination_unit/coordination_unit_impl.h
diff --git a/services/resource_coordinator/coordination_unit/coordination_unit_impl.h b/services/resource_coordinator/coordination_unit/coordination_unit_impl.h
index 492c34c973d6afb55e3b48731f36963b74304af1..2c74cc0254d2bf57ceba5aa007c54330a088f66b 100644
--- a/services/resource_coordinator/coordination_unit/coordination_unit_impl.h
+++ b/services/resource_coordinator/coordination_unit/coordination_unit_impl.h
@@ -14,6 +14,7 @@
 #include <vector>
 
 #include "base/callback.h"
+#include "base/observer_list.h"
 #include "base/optional.h"
 #include "base/values.h"
 #include "mojo/public/cpp/bindings/binding_set.h"
@@ -29,60 +30,6 @@ namespace resource_coordinator {
 
 class CoordinationUnitGraphObserver;
 
-// Collection to manage CoordinationUnitEvent listeners.
-template <typename Filter>
-class CoordinationUnitGraphObserverRegistry {
- public:
-  CoordinationUnitGraphObserverRegistry() = default;
-  ~CoordinationUnitGraphObserverRegistry() = default;
-
-  // callbacks paired with this kNoFilter will always be invoked
-  static const Filter kNoFilter = static_cast<Filter>(0);
-
-  void AddObserver(CoordinationUnitGraphObserver* observer, Filter filter) {
-    registry_[filter].push_back(observer);
-  }
-
-  void AddObserver(CoordinationUnitGraphObserver* observer) {
-    AddObserver(observer, kNoFilter);
-  }
-
-  // Get the observers who are are either registered to be invoked for
-  // a specific filter or were registered with the kNoFilter.
-  // TODO(matthalp) add iterator support to replace this call and
-  // avoid excessive copying that currently occurs
-  std::vector<CoordinationUnitGraphObserver*> GetObserversForFilter(
-      Filter filter) {
-    std::vector<CoordinationUnitGraphObserver*> observers;
-
-    // Get listeners registered with a listener first.
-    AppendObservers(&observers, filter);
-
-    // Get listeners registered without a filter after.
-    if (filter != kNoFilter) {
-      AppendObservers(&observers, kNoFilter);
-    }
-
-    return observers;
-  }
-
-  std::vector<CoordinationUnitGraphObserver*> GetObserversWithoutAFilter() {
-    return GetObserversForFilter(kNoFilter);
-  }
-
- private:
-  void AppendObservers(std::vector<CoordinationUnitGraphObserver*>* observers,
-                       Filter filter) {
-    observers->insert(observers->end(), registry_[filter].begin(),
-                      registry_[filter].end());
-  }
-
-  // TODO(matthalp) Consider using a std::unordered_map instead.
-  std::map<Filter, std::vector<CoordinationUnitGraphObserver*>> registry_;
-
-  DISALLOW_COPY_AND_ASSIGN(CoordinationUnitGraphObserverRegistry);
-};
-
 class CoordinationUnitImpl : public mojom::CoordinationUnit {
  public:
   CoordinationUnitImpl(
@@ -119,26 +66,8 @@ class CoordinationUnitImpl : public mojom::CoordinationUnit {
   // Set property from internal key-value store
   void SetProperty(mojom::PropertyType property, base::Value value);
 
-  // Notify an instance it will be destroyed before its destructor is
-  // actually called.
-  void WillBeDestroyed();
-
-  void ObserveOnChildAddedEvent(CoordinationUnitGraphObserver* observer,
-                                CoordinationUnitType child_filter);
-  void ObserveOnChildAddedEvent(CoordinationUnitGraphObserver* observer);
-  void ObserveOnParentAddedEvent(CoordinationUnitGraphObserver* observer,
-                                 CoordinationUnitType parent_filter);
-  void ObserveOnParentAddedEvent(CoordinationUnitGraphObserver* observer);
-  void ObserveOnPropertyChangedEvent(CoordinationUnitGraphObserver* observer,
-                                     mojom::PropertyType property_filter);
-  void ObserveOnPropertyChangedEvent(CoordinationUnitGraphObserver* observer);
-  void ObserveOnChildRemovedEvent(CoordinationUnitGraphObserver* observer,
-                                  CoordinationUnitType child_filter);
-  void ObserveOnChildRemovedEvent(CoordinationUnitGraphObserver* observer);
-  void ObserveOnParentRemovedEvent(CoordinationUnitGraphObserver* observer,
-                                   CoordinationUnitType parent_filter);
-  void ObserveOnParentRemovedEvent(CoordinationUnitGraphObserver* observer);
-  void ObserveOnWillBeDestroyedEvent(CoordinationUnitGraphObserver* observer);
+  void AddObserver(CoordinationUnitGraphObserver* observer);
+  void RemoveObserver(CoordinationUnitGraphObserver* observer);
 
  protected:
   const CoordinationUnitID id_;
@@ -173,22 +102,9 @@ class CoordinationUnitImpl : public mojom::CoordinationUnit {
   mojom::CoordinationPolicyCallbackPtr policy_callback_;
   mojom::CoordinationPolicyPtr current_policy_;
 
-  base::Optional<bool> state_flags_[kNumStateFlags];
+  base::ObserverList<CoordinationUnitGraphObserver> observers_;
 
-  CoordinationUnitGraphObserverRegistry<CoordinationUnitType>
-      on_child_added_event_observer_registry_;
-  CoordinationUnitGraphObserverRegistry<CoordinationUnitType>
-      on_parent_added_event_observer_registry_;
-  CoordinationUnitGraphObserverRegistry<CoordinationUnitType>
-      on_child_removed_event_observer_registry_;
-  CoordinationUnitGraphObserverRegistry<CoordinationUnitType>
-      on_parent_removed_event_observer_registry_;
-  CoordinationUnitGraphObserverRegistry<mojom::PropertyType>
-      on_property_changed_event_observer_registry_;
-  // There is nothing to filter WillBeDestroyedEventCallbacks on so the
-  // CoordinationUnitType is used as a filter placeholder
-  CoordinationUnitGraphObserverRegistry<CoordinationUnitType>
-      on_will_be_destroyed_event_observer_registry_;
+  base::Optional<bool> state_flags_[kNumStateFlags];
 
   DISALLOW_COPY_AND_ASSIGN(CoordinationUnitImpl);
 };