[Athena] Simple pull to refresh implementation

content/public/browser/web_contents_delegate.h

Index: content/public/browser/web_contents_delegate.h
diff --git a/content/public/browser/web_contents_delegate.h b/content/public/browser/web_contents_delegate.h
index 0f630f3b9006ec76b1ca3c0103ddd24e01f208f7..457b3c0595076b328181605c646afb07023d34c8 100644
--- a/content/public/browser/web_contents_delegate.h
+++ b/content/public/browser/web_contents_delegate.h
@@ -162,9 +162,12 @@ class CONTENT_EXPORT WebContentsDelegate {
   virtual bool CanOverscrollContent() const;
 
   // Callback that allows vertical overscroll activies to be communicated to the
-  // delegate.
+  // delegate. |delta_y| is the total amount of overscroll.
   virtual void OverscrollUpdate(int delta_y) {}
 
+  // Invoked when a vertical overscroll completes.
+  virtual void OverscrollComplete() {}
+
   // Return the rect where to display the resize corner, if any, otherwise
   // an empty rect.
   virtual gfx::Rect GetRootWindowResizerRect() const;