Split infobar_delegate.[cc,h] into separate pieces for the different classes defined within, so that

chrome/browser/ui/cocoa/infobars/infobar_controller.mm

Index: chrome/browser/ui/cocoa/infobars/infobar_controller.mm
diff --git a/chrome/browser/ui/cocoa/infobars/infobar_controller.mm b/chrome/browser/ui/cocoa/infobars/infobar_controller.mm
index a2c565fc458e04f14146084a881b00ea8b2c8016..0c9967a8378398d3dae1c0a95d83731d0b7f6ef2 100644
--- a/chrome/browser/ui/cocoa/infobars/infobar_controller.mm
+++ b/chrome/browser/ui/cocoa/infobars/infobar_controller.mm
@@ -7,7 +7,8 @@
 #include "base/logging.h"  // for NOTREACHED()
 #include "base/mac/mac_util.h"
 #include "base/sys_string_conversions.h"
-#include "chrome/browser/tab_contents/infobar_delegate.h"
+#include "chrome/browser/tab_contents/confirm_infobar_delegate.h"
+#include "chrome/browser/tab_contents/link_infobar_delegate.h"
 #import "chrome/browser/ui/cocoa/animatable_view.h"
 #include "chrome/browser/ui/cocoa/event_utils.h"
 #include "chrome/browser/ui/cocoa/infobars/infobar.h"