Adds the UserInputMonitor implementation for Mac.

media/base/user_input_monitor.h

Index: media/base/user_input_monitor.h
diff --git a/media/base/user_input_monitor.h b/media/base/user_input_monitor.h
index 9eb82f334f833612a0720367c83c4513ba275bef..91fa311d73c1dee6397a59b8ac45cc751e07600d 100644
--- a/media/base/user_input_monitor.h
+++ b/media/base/user_input_monitor.h
@@ -9,7 +9,6 @@
 
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
-#include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
 #include "base/synchronization/lock.h"
 #include "media/base/media_export.h"
@@ -28,6 +27,8 @@ namespace media {
 // Thread safe. The thread on which the listenters are called is not guaranteed.
 // The callers should not perform expensive/blocking tasks in the callback since
 // it might be called on the browser UI/IO threads.
+// The object must outlive the browser UI/IO threads to make sure the callbacks
+// will not access deleted object.
 class MEDIA_EXPORT UserInputMonitor {
  public:
   // The interface to receive mouse movement events.
@@ -39,17 +40,6 @@ class MEDIA_EXPORT UserInputMonitor {
    protected:
     virtual ~MouseEventListener() {}
   };
-  // The interface to receive key stroke events.
-  class MEDIA_EXPORT KeyStrokeListener {
-   public:
-    // Called when any key is pressed. Called only once until the key is
-    // released, i.e. holding down a key for a long period will generate one
-    // callback just when the key is pressed down.
-    virtual void OnKeyStroke() = 0;
-
-   protected:
-    virtual ~KeyStrokeListener() {}
-  };
 
   virtual ~UserInputMonitor();
 
@@ -65,8 +55,15 @@ class MEDIA_EXPORT UserInputMonitor {
   // destroyed.
   void AddMouseListener(MouseEventListener* listener);
   void RemoveMouseListener(MouseEventListener* listener);
-  void AddKeyStrokeListener(KeyStrokeListener* listener);
-  void RemoveKeyStrokeListener(KeyStrokeListener* listener);
+
+  // The callers must call AddKeyPressCounterReference before calling
+  // GetKeyPressCount(), and call ReleaseKeyPressCounterReference when it no
+  // longer needs it.
+  void AddKeyPressCounterReference();
+  void ReleaseKeyPressCounterReference();
+  // Returns the number of Key presses since the first KeyPressCounterReference
+  // is added. Auto-repeated key presses are not counted.
+  virtual size_t GetKeyPressCount() const;
 
  protected:
   UserInputMonitor();
@@ -82,14 +79,14 @@ class MEDIA_EXPORT UserInputMonitor {
   virtual void StartKeyboardMonitoring() = 0;
   virtual void StopKeyboardMonitoring() = 0;
 
-  base::Lock lock_;
+  mutable base::Lock lock_;
   ObserverList<MouseEventListener, true> mouse_listeners_;
-  ObserverList<KeyStrokeListener, true> key_stroke_listeners_;
   bool monitoring_mouse_;
-  bool monitoring_keyboard_;
+  size_t key_press_counter_references_;
   // The set of keys currently held down. Used for convering raw keyboard events
   // into KeyStrokeListener callbacks.
-  std::set<ui::KeyboardCode> pressed_keys_;
+  std::set<int> pressed_keys_;
+  size_t total_key_presses_;

[DaleCurtis, 2013/08/22 22:07:34]

Shouldn't this just be pressed_keys_.size() ?

[jiayl, 2013/08/22 22:23:22]

No. If you press and release a key, pressed_keys_.size() will be zero and the
event is lost. This is the total number of key presses, not the currently
pressed keys.

 
   DISALLOW_COPY_AND_ASSIGN(UserInputMonitor);
 };