Wheel scroll latching enabled behind flag.

content/browser/renderer_host/input/mouse_wheel_event_queue.h

Index: content/browser/renderer_host/input/mouse_wheel_event_queue.h
diff --git a/content/browser/renderer_host/input/mouse_wheel_event_queue.h b/content/browser/renderer_host/input/mouse_wheel_event_queue.h
index a2722310b74b68c0c7e5c3f261851c65a969432d..161dfbb0aab8bf59443219e0ebc5ecfa8e3b26b8 100644
--- a/content/browser/renderer_host/input/mouse_wheel_event_queue.h
+++ b/content/browser/renderer_host/input/mouse_wheel_event_queue.h
@@ -19,7 +19,8 @@ namespace content {
 // ScrollUpdate was sent for wheel based gesture scrolls.
 // Set the default wheel transaction to 0ms until
 // crbug.com/526463 is fully implemented.
-const int64_t kDefaultWheelScrollTransactionMs = 0;  // 100;
+const int64_t kDefaultWheelScrollTransactionMs = 0;
+const int64_t kDefaultWheelScrollLatchingTransactionMs = 100;
 
 class QueuedWebMouseWheelEvent;
 
@@ -47,7 +48,7 @@ class CONTENT_EXPORT MouseWheelEventQueue {
   // |scroll_transaction_ms| is the duration in which the
   // ScrollEnd should be sent after a ScrollUpdate.
   MouseWheelEventQueue(MouseWheelEventQueueClient* client,
-                       int64_t scroll_transaction_ms);
+                       bool touchpad_scroll_latching);
 
   ~MouseWheelEventQueue();
 
@@ -97,6 +98,9 @@ class CONTENT_EXPORT MouseWheelEventQueue {
   // GSB has been sent in the past.
   bool needs_scroll_end_;
 
+  // True if the touchpad scroll latching is enabled.
+  bool touchpad_scroll_latching_;
+
   int64_t scroll_transaction_ms_;
   blink::WebGestureDevice scrolling_device_;