Experimental Extension Keybinding (first cut).

ui/base/accelerators/accelerator_manager.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_BASE_ACCELERATORS_ACCELERATOR_MANAGER_H_
 #define UI_BASE_ACCELERATORS_ACCELERATOR_MANAGER_H_
 #pragma once
 
 #include <list>
 #include <map>
+#include <utility>
 
 #include "base/basictypes.h"
 #include "ui/base/accelerators/accelerator.h"
 #include "ui/base/events.h"
 #include "ui/base/ui_export.h"
 
 namespace ui {
 
 // The AcceleratorManger is used to handle keyboard accelerators.
 class UI_EXPORT AcceleratorManager {
  public:
+  enum HandlerPriority {
+    kNormalPriority,
+    kHighPriority,
+  };
+
   AcceleratorManager();
   ~AcceleratorManager();
 
   // Register a keyboard accelerator for the specified target. If multiple
   // targets are registered for an accelerator, a target registered later has
   // higher priority.
+  // |accelerator| is the accelerator to register.
+  // |priority| denotes the priority of the handler.
+  // NOTE: In almost all cases, you should specify kPriorityNormal for this
+  // parameter. Setting it to kPriorityHigh prevents Chrome from sending the
+  // shortcut to the webpage if the renderer has focus, which is not desirable
+  // except for very isolated cases.
+  // |target| is the AcceleratorTarget that handles the event once the
+  // accelerator is pressed.
   // Note that we are currently limited to accelerators that are either:
   // - a key combination including Ctrl or Alt
   // - the escape key
   // - the enter key
   // - any F key (F1, F2, F3 ...)
   // - any browser specific keys (as available on special keyboards)
-  void Register(const Accelerator& accelerator, AcceleratorTarget* target);
+  void Register(const Accelerator& accelerator,
+                HandlerPriority priority,
+                AcceleratorTarget* target);
 
   // Unregister the specified keyboard accelerator for the specified target.
   void Unregister(const Accelerator& accelerator, AcceleratorTarget* target);
 
   // Unregister all keyboard accelerator for the specified target.
   void UnregisterAll(AcceleratorTarget* target);
 
   // Activate the target associated with the specified accelerator.
   // First, AcceleratorPressed handler of the most recently registered target
   // is called, and if that handler processes the event (i.e. returns true),
   // this method immediately returns. If not, we do the same thing on the next
   // target, and so on.
   // Returns true if an accelerator was activated.
   bool Process(const Accelerator& accelerator);
 
   // Returns the AcceleratorTarget that should be activated for the specified
   // keyboard accelerator, or NULL if no view is registered for that keyboard
   // accelerator.
   AcceleratorTarget* GetCurrentTarget(const Accelerator& accelertor) const;
 
+  // Whether the given |accelerator| has a priority handler associated with it.
+  bool HasPriorityHandler(const Accelerator& accelerator) const;
+
  private:
   bool ShouldHandle(const Accelerator& accelerator) const;
 
   // The accelerators and associated targets.
   typedef std::list<AcceleratorTarget*> AcceleratorTargetList;
-  typedef std::map<Accelerator, AcceleratorTargetList> AcceleratorMap;
+  // 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;
   AcceleratorMap accelerators_;
 
   // An event passed to Process() last time.
   EventType last_event_type_;
 
   DISALLOW_COPY_AND_ASSIGN(AcceleratorManager);
 };
 
 }  // namespace ui
 
 #endif  // UI_BASE_ACCELERATORS_ACCELERATOR_MANAGER_H_