Remove some dead scrolling paths and unused params

public/web/WebWidgetClient.h

Index: public/web/WebWidgetClient.h
diff --git a/public/web/WebWidgetClient.h b/public/web/WebWidgetClient.h
index 63a0e62e14968c4224fc880d603188105633e19d..8ee3f4dbd1ecb64ead9e077d0bee2764afd16302 100644
--- a/public/web/WebWidgetClient.h
+++ b/public/web/WebWidgetClient.h
@@ -31,6 +31,8 @@
 #ifndef WebWidgetClient_h
 #define WebWidgetClient_h
 
+#define DID_SCROLL_RECT_DOES_NOT_EXIST 1
+
 #include "WebNavigationPolicy.h"
 #include "public/platform/WebCommon.h"
 #include "public/platform/WebLayerTreeView.h"
@@ -51,10 +53,6 @@ public:
     // Called when a region of the WebWidget needs to be re-painted.
     virtual void didInvalidateRect(const WebRect&) { }
 
-    // Called when a region of the WebWidget, given by clipRect, should be
-    // scrolled by the specified dx and dy amounts.
-    virtual void didScrollRect(int dx, int dy, const WebRect& clipRect) { }
-
     // Called when the Widget has changed size as a result of an auto-resize.
     virtual void didAutoResize(const WebSize& newSize) { }