Replace MouseWheel events with GestureScrollBegin in WebContentsObserver::DidGetUserInteraction

content/browser/renderer_host/render_widget_host_impl.cc

Index: content/browser/renderer_host/render_widget_host_impl.cc
diff --git a/content/browser/renderer_host/render_widget_host_impl.cc b/content/browser/renderer_host/render_widget_host_impl.cc
index 996e2e7409decc16f4467a957dc267d63643e304..1a2bab424140251838038b9dcb59e66b62aace0a 100644
--- a/content/browser/renderer_host/render_widget_host_impl.cc
+++ b/content/browser/renderer_host/render_widget_host_impl.cc
@@ -98,13 +98,6 @@ using blink::WebTextDirection;
 namespace content {
 namespace {
 
-// The amount of time after a mouse wheel event is sent to the delegate
-// OnUserInteraction method before another mouse wheel event will be sent. This
-// interval is used by the Blink EventHandler in its orthogonal heuristic for
-// detecting the end of a scroll event (if no event has been seen in 0.1
-// seconds, send an end scroll).
-const double kMouseWheelCoalesceIntervalInSeconds = 0.1;
-
 bool g_check_for_pending_resize_ack = true;
 
 // <process id, routing id>
@@ -218,7 +211,6 @@ RenderWidgetHostImpl::RenderWidgetHostImpl(RenderWidgetHostDelegate* delegate,
           base::TimeDelta::FromMilliseconds(kHungRendererDelayMs)),
       new_content_rendering_delay_(
           base::TimeDelta::FromMilliseconds(kNewContentRenderingDelayMs)),
-      mouse_wheel_coalesce_timer_(new base::ElapsedTimer()),
       weak_factory_(this) {
   CHECK(delegate_);
   CHECK_NE(MSG_ROUTING_NONE, routing_id_);
@@ -1900,21 +1892,11 @@ InputEventAckState RenderWidgetHostImpl::FilterInputEvent(
   if (!process_->HasConnection())
     return INPUT_EVENT_ACK_STATE_UNKNOWN;
 
-  if (delegate_) {
-    if (event.type == WebInputEvent::MouseDown ||
-        event.type == WebInputEvent::GestureTapDown ||
-        event.type == WebInputEvent::RawKeyDown) {
-      delegate_->OnUserInteraction(this, event.type);
-    } else if (event.type == WebInputEvent::MouseWheel) {
-      if (mouse_wheel_coalesce_timer_->Elapsed().InSecondsF() >
-          kMouseWheelCoalesceIntervalInSeconds) {
-        // TODO(dominickn): once GestureScrollBegin has landed on all platforms,
-        // replace this branch and remove.
-        delegate_->OnUserInteraction(this, event.type);
-      }
-
-      mouse_wheel_coalesce_timer_.reset(new base::ElapsedTimer());
-    }
+  if (delegate_ && (event.type == WebInputEvent::MouseDown ||
+                    event.type == WebInputEvent::GestureScrollBegin ||
+                    event.type == WebInputEvent::GestureTapDown ||
+                    event.type == WebInputEvent::RawKeyDown)) {
+    delegate_->OnUserInteraction(this, event.type);
   }
 
   return view_ ? view_->FilterInputEvent(event)