Make mash register initial batch of accelerators in single shot.

ui/base/accelerators/accelerator_manager_delegate.h

Index: ui/base/accelerators/accelerator_manager_delegate.h
diff --git a/ui/base/accelerators/accelerator_manager_delegate.h b/ui/base/accelerators/accelerator_manager_delegate.h
index e3c6d9ccf6e53ebee773c721a1374ae0b03e18c0..52bcb7dfd728a0c5af7675e098545d7205491a2c 100644
--- a/ui/base/accelerators/accelerator_manager_delegate.h
+++ b/ui/base/accelerators/accelerator_manager_delegate.h
@@ -22,6 +22,13 @@ class UI_BASE_EXPORT AcceleratorManagerDelegate {
   // Called when there no more targets are registered for |accelerator|.
   virtual void OnAcceleratorUnregistered(const Accelerator& accelerator) = 0;
 
+  // Called when a number of accelerators are registered at once. An accelerator
+  // is only included in the |accelerators| vector when the first time a target
+  // for the accelerator is registered. For example, if Register() is called
+  // twice with the same accelerator, this is called only for the first call.
+  virtual void OnAcceleratorsRegistered(
+      const std::vector<ui::Accelerator>& accelerators) = 0;
+
  protected:
   virtual ~AcceleratorManagerDelegate() {}
 };