Adding metrics logging for Simplified Gesture Navigation.

content/browser/web_contents/aura/overscroll_navigation_overlay.h

Index: content/browser/web_contents/aura/overscroll_navigation_overlay.h
diff --git a/content/browser/web_contents/aura/overscroll_navigation_overlay.h b/content/browser/web_contents/aura/overscroll_navigation_overlay.h
index 44739c973829be484938104ca6419fcff6e8be6a..4f69dde8974731bdc409a1df785ee43e1483d02b 100644
--- a/content/browser/web_contents/aura/overscroll_navigation_overlay.h
+++ b/content/browser/web_contents/aura/overscroll_navigation_overlay.h
@@ -8,6 +8,7 @@
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "content/browser/web_contents/aura/overscroll_window_animation.h"
+#include "content/browser/web_contents/aura/types.h"
 #include "content/browser/web_contents/web_contents_view_aura.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/web_contents_observer.h"
@@ -32,8 +33,6 @@ class CONTENT_EXPORT OverscrollNavigationOverlay
     : public WebContentsObserver,
       public OverscrollWindowAnimation::Delegate {
  public:
-  enum NavigationDirection { NONE, FORWARD, BACK, NAVIGATION_COUNT };
-
   OverscrollNavigationOverlay(WebContentsImpl* web_contents,
                               aura::Window* web_contents_window);