Send an EVENT_SYSTEM_ALERT when a user first places focus within an infobar.

chrome/browser/views/infobars/infobars.h

Index: chrome/browser/views/infobars/infobars.h
===================================================================
--- chrome/browser/views/infobars/infobars.h	(revision 60349)
+++ chrome/browser/views/infobars/infobars.h	(working copy)
@@ -11,6 +11,7 @@
 #include "chrome/browser/tab_contents/infobar_delegate.h"
 #include "views/controls/button/button.h"
 #include "views/controls/link.h"
+#include "views/focus/focus_manager.h"
 
 class InfoBarContainer;
 class SlideAnimation;
@@ -41,6 +42,7 @@
 
 class InfoBar : public views::View,
                 public views::ButtonListener,
+                public views::FocusChangeListener,
                 public AnimationDelegate {
  public:
   explicit InfoBar(InfoBarDelegate* delegate);
@@ -99,6 +101,9 @@
   // Overridden from views::ButtonListener:
   virtual void ButtonPressed(views::Button* sender, const views::Event& event);
 
+  // Overridden from views::FocusChangeListener:
+  virtual void FocusWillChange(View* focused_before, View* focused_now);
+
   // Overridden from AnimationDelegate:
   virtual void AnimationProgressed(const Animation* animation);
   virtual void AnimationEnded(const Animation* animation);