Refactor TouchSelectionDraggableClient APIs

ui/touch_selection/touch_handle.cc

Index: ui/touch_selection/touch_handle.cc
diff --git a/ui/touch_selection/touch_handle.cc b/ui/touch_selection/touch_handle.cc
index 0fe3612eab31714ea616529d42ad28eb635c944d..a65ba49a665d6d681fbc313353a831759125261f 100644
--- a/ui/touch_selection/touch_handle.cc
+++ b/ui/touch_selection/touch_handle.cc
@@ -195,7 +195,8 @@ bool TouchHandle::WillHandleTouchEvent(const MotionEvent& event) {
 
       // Note that we signal drag update even if we're inside the tap region,
       // as there are cases where characters are narrower than the slop length.
-      client_->OnDragUpdate(*this, touch_move_position + touch_drag_offset_);
+      client_->OnDragEvent(HANDLE_DRAG_UPDATE, *this,
+                           touch_move_position + touch_drag_offset_);
     } break;
 
     case MotionEvent::ACTION_UP: {
@@ -337,7 +338,7 @@ void TouchHandle::BeginDrag() {
   EndFade();
   is_dragging_ = true;
   is_drag_within_tap_region_ = true;
-  client_->OnDragBegin(*this, focus_bottom());
+  client_->OnDragEvent(HANDLE_DRAG_BEGIN, *this, focus_bottom());
 }
 
 void TouchHandle::EndDrag() {
@@ -347,7 +348,7 @@ void TouchHandle::EndDrag() {
 
   is_dragging_ = false;
   is_drag_within_tap_region_ = false;
-  client_->OnDragEnd(*this);
+  client_->OnDragEvent(HANDLE_DRAG_BEGIN, *this, focus_bottom());
 
   if (deferred_orientation_ != TouchHandleOrientation::UNDEFINED) {
     TouchHandleOrientation deferred_orientation = deferred_orientation_;