Wheel scroll latching enabled behind flag.

content/browser/renderer_host/input/mouse_wheel_event_queue.cc

Index: content/browser/renderer_host/input/mouse_wheel_event_queue.cc
diff --git a/content/browser/renderer_host/input/mouse_wheel_event_queue.cc b/content/browser/renderer_host/input/mouse_wheel_event_queue.cc
index d1d3bc22276279290e8cde1271e27591b76b26e3..fe72bb56e3705a1e7694ff136b02ac82e27b55f7 100644
--- a/content/browser/renderer_host/input/mouse_wheel_event_queue.cc
+++ b/content/browser/renderer_host/input/mouse_wheel_event_queue.cc
@@ -34,13 +34,16 @@ class QueuedWebMouseWheelEvent : public MouseWheelEventWithLatencyInfo {
 };
 
 MouseWheelEventQueue::MouseWheelEventQueue(MouseWheelEventQueueClient* client,
-                                           int64_t scroll_transaction_ms)
+                                           bool touchpad_scroll_latching)
     : client_(client),
       needs_scroll_begin_(true),
       needs_scroll_end_(false),
-      scroll_transaction_ms_(scroll_transaction_ms),
+      touchpad_scroll_latching_(touchpad_scroll_latching),

[nasko, 2016/07/25 16:00:18]

It doesn't seem this member variable is used anywhere in this class. Can't we
just set the scroll_transaction_ms_ based on the constructor parameter and
remove the member?

[sahel, 2016/07/25 16:05:11]

You are right, for now it is not used. But I am working on a dependent patch
that uses this flag to latch the touchpad scrolls. (we discussed with tdresser@
and he recommended to split the previous cl into two.) I didn't want to revert
it to use the number in constructor and then change it back to this boolean
parameter.

       scrolling_device_(blink::WebGestureDeviceUninitialized) {
   DCHECK(client);
+  scroll_transaction_ms_ = touchpad_scroll_latching_

[tdresser, 2016/07/25 16:46:55]

The timeout is only for wheel, not touchpad, right?
So this bool is named incorrectly?

[sahel, 2016/07/25 17:58:26]

Done.

+                               ? kDefaultWheelScrollLatchingTransactionMs
+                               : kDefaultWheelScrollTransactionMs;
 }
 
 MouseWheelEventQueue::~MouseWheelEventQueue() {