Bring up idletimer unittest on Mac port.

base/idle_timer.h

Index: base/idle_timer.h
===================================================================
--- base/idle_timer.h	(revision 3254)
+++ base/idle_timer.h	(working copy)
@@ -28,7 +28,9 @@
 #ifndef BASE_IDLE_TIMER_H_
 #define BASE_IDLE_TIMER_H_
 
+#if defined(OS_WIN)
 #include <windows.h>
+#endif
 
 #include "base/basictypes.h"
 #include "base/task.h"
@@ -36,8 +38,9 @@
 
 namespace base {
 
-// Function prototype for GetLastInputInfo.
-typedef BOOL (__stdcall *GetLastInputInfoFunction)(PLASTINPUTINFO plii);
+// Function prototype - Get the number of milliseconds that the user has been
+// idle.
+typedef bool (*IdleTimeSource)(int32 *milliseconds_interval_since_last_event);
 
 class IdleTimer {
  public:
@@ -60,9 +63,9 @@
   virtual void OnIdle() = 0;
 
  protected:
-  // Override the GetLastInputInfo function.
-  void set_last_input_info_fn(GetLastInputInfoFunction function) {
-    get_last_input_info_fn_ = function;
+  // Override the IdleTimeSource.
+  void set_idle_time_source(IdleTimeSource idle_time_source) {
+    idle_time_source_ = idle_time_source;
   }
 
  private:
@@ -84,7 +87,7 @@
                           // will be 0 until the timer fires the first time.
   OneShotTimer<IdleTimer> timer_;
 
-  GetLastInputInfoFunction get_last_input_info_fn_;
+  IdleTimeSource idle_time_source_;
 
   DISALLOW_COPY_AND_ASSIGN(IdleTimer);
 };