[not for review - epic CL] Adding Elastic+Momentum+Layered scrolling to views::ScrollView

cc/input/input_handler.h

Index: cc/input/input_handler.h
diff --git a/cc/input/input_handler.h b/cc/input/input_handler.h
index 11a33105b1ef87efc0eaedb2827dffa97b8eb73d..d75c667e83996cbb096f8a6a45e68946d02d1658 100644
--- a/cc/input/input_handler.h
+++ b/cc/input/input_handler.h
@@ -8,6 +8,7 @@
 #include <memory>
 
 #include "base/macros.h"
+#include "base/memory/weak_ptr.h"
 #include "base/time/time.h"
 #include "cc/base/cc_export.h"
 #include "cc/input/event_listener_properties.h"
@@ -196,7 +197,11 @@ class CC_EXPORT InputHandler {
   virtual std::unique_ptr<SwapPromiseMonitor>
   CreateLatencyInfoSwapPromiseMonitor(ui::LatencyInfo* latency) = 0;
 
-  virtual ScrollElasticityHelper* CreateScrollElasticityHelper() = 0;
+  virtual ScrollElasticityHelper* CreateRootScrollElasticityHelper() = 0;
+  virtual base::WeakPtr<ScrollElasticityHelper>
+  ScrollElasticityHelperForScrollingLayer() = 0;
+  virtual gfx::ScrollOffset GetScrollOffsetForLayer(int layer_id) = 0;
+  virtual bool ScrollLayerTo(int layer_id, const gfx::ScrollOffset& offset) = 0;
 
  protected:
   InputHandler() {}