Adds AcceleratorManagerDelegate

ui/base/accelerators/accelerator_manager.h

Index: ui/base/accelerators/accelerator_manager.h
diff --git a/ui/base/accelerators/accelerator_manager.h b/ui/base/accelerators/accelerator_manager.h
index d103e6fb1706b17c1259550345951f3107a009e4..9db9629fd8ecc8a9aabf7fa974fe15f1af2cdd75 100644
--- a/ui/base/accelerators/accelerator_manager.h
+++ b/ui/base/accelerators/accelerator_manager.h
@@ -16,7 +16,10 @@
 
 namespace ui {
 
-// The AcceleratorManger is used to handle keyboard accelerators.
+class AcceleratorManagerDelegate;
+
+// AcceleratorManger handles processing of accelerators. A delegate may be
+// supplied which is notified as unique accelerators are added and removed.
 class UI_BASE_EXPORT AcceleratorManager {
  public:
   enum HandlerPriority {
@@ -24,7 +27,7 @@ class UI_BASE_EXPORT AcceleratorManager {
     kHighPriority,
   };
 
-  AcceleratorManager();
+  explicit AcceleratorManager(AcceleratorManagerDelegate* = nullptr);
   ~AcceleratorManager();
 
   // Register a keyboard accelerator for the specified target. If multiple
@@ -70,11 +73,18 @@ class UI_BASE_EXPORT AcceleratorManager {
 
  private:
   // The accelerators and associated targets.
-  typedef std::list<AcceleratorTarget*> AcceleratorTargetList;
+  using AcceleratorTargetList = std::list<AcceleratorTarget*>;
   // This construct pairs together a |bool| (denoting whether the list contains
   // a priority_handler at the front) with the list of AcceleratorTargets.
-  typedef std::pair<bool, AcceleratorTargetList> AcceleratorTargets;
-  typedef std::map<Accelerator, AcceleratorTargets> AcceleratorMap;
+  using AcceleratorTargets = std::pair<bool, AcceleratorTargetList>;
+  using AcceleratorMap = std::map<Accelerator, AcceleratorTargets>;
+
+  // Implementation of Unregister(). |map_iter| points to the accelerator to
+  // remove, and |target| the AcceleratorTarget to remove.
+  void UnregisterImpl(AcceleratorMap::iterator map_iter,
+                      AcceleratorTarget* target);
+
+  AcceleratorManagerDelegate* delegate_;
   AcceleratorMap accelerators_;
 
   DISALLOW_COPY_AND_ASSIGN(AcceleratorManager);