Adds the UserInputMonitor implementation for Mac.

media/base/user_input_monitor_linux.cc

Index: media/base/user_input_monitor_linux.cc
diff --git a/media/base/user_input_monitor_linux.cc b/media/base/user_input_monitor_linux.cc
index ee1b7749fd213569d2dbf2db8803a60b0b4b0d06..30d87171b9439530e021cd88454c869046c46774 100644
--- a/media/base/user_input_monitor_linux.cc
+++ b/media/base/user_input_monitor_linux.cc
@@ -21,6 +21,7 @@
 #include "base/posix/eintr_wrapper.h"
 #include "base/single_thread_task_runner.h"
 #include "base/threading/non_thread_safe.h"
+#include "media/base/keyboard_event_counter.h"
 #include "third_party/skia/include/core/SkPoint.h"
 #include "ui/base/keycodes/keyboard_code_conversion_x.h"
 
@@ -37,10 +38,12 @@ namespace {
 class UserInputMonitorLinux : public base::NonThreadSafe,
                               public UserInputMonitor {
  public:
-  UserInputMonitorLinux(
+  explicit UserInputMonitorLinux(
       const scoped_refptr<base::SingleThreadTaskRunner>& io_task_runner);
   virtual ~UserInputMonitorLinux();
 
+  virtual size_t GetKeyPressCount() const OVERRIDE;
+
  private:
   enum EventType {
     MOUSE_EVENT,
@@ -98,6 +101,7 @@ class UserInputMonitorLinux : public base::NonThreadSafe,
   // Task runner on which X Window events are received.
   scoped_refptr<base::SingleThreadTaskRunner> io_task_runner_;
   scoped_refptr<Core> core_;
+  KeyboardEventCounter counter_;
 
   DISALLOW_COPY_AND_ASSIGN(UserInputMonitorLinux);
 };
@@ -112,6 +116,10 @@ UserInputMonitorLinux::UserInputMonitorLinux(
 
 UserInputMonitorLinux::~UserInputMonitorLinux() {}
 
+size_t UserInputMonitorLinux::GetKeyPressCount() const {
+  return counter_.GetKeyPressCount();
+}
+
 void UserInputMonitorLinux::StartMouseMonitoring() {
   io_task_runner_->PostTask(
       FROM_HERE, base::Bind(&Core::StartMonitor, core_.get(), MOUSE_EVENT));
@@ -123,6 +131,7 @@ void UserInputMonitorLinux::StopMouseMonitoring() {
 }
 
 void UserInputMonitorLinux::StartKeyboardMonitoring() {
+  counter_.Reset();
   io_task_runner_->PostTask(
       FROM_HERE, base::Bind(&Core::StartMonitor, core_.get(), KEYBOARD_EVENT));
 }
@@ -138,7 +147,7 @@ void UserInputMonitorLinux::OnMouseEvent(const SkIPoint& position) {
 
 void UserInputMonitorLinux::OnKeyboardEvent(ui::EventType event,
                                             ui::KeyboardCode key_code) {
-  UserInputMonitor::OnKeyboardEvent(event, key_code);
+  counter_.OnKeyboardEvent(event, key_code);
 }
 
 UserInputMonitorLinux::Core::Core(const MouseCallback& mouse_callback,