Touch Action could cause wheel gestures to be filtered.

content/browser/web_contents/web_contents_view_aura_browsertest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/web_contents/web_contents_view_aura.h"
 
 #include <stddef.h>
 
 #include "base/command_line.h"
 #include "base/location.h"
@@ skipping 939 matching lines @@
     ASSERT_EQ(INPUT_EVENT_ACK_STATE_NOT_CONSUMED, filter()->last_ack_state());
 
     // Send first touch move, and then a scroll begin.
     touch.MovePoint(0, bounds.x() + 20 + 1 * dx, bounds.y() + 100);
     GetRenderWidgetHost()->ForwardTouchEventWithLatencyInfo(touch,
                                                             ui::LatencyInfo());
     filter()->WaitForAck(blink::WebInputEvent::TouchMove);
     ASSERT_EQ(INPUT_EVENT_ACK_STATE_NOT_CONSUMED, filter()->last_ack_state());
 
     blink::WebGestureEvent scroll_begin =
-        SyntheticWebGestureEventBuilder::BuildScrollBegin(1, 1);
+        SyntheticWebGestureEventBuilder::BuildScrollBegin(
+            1, 1, blink::WebGestureDeviceTouchscreen);
     GetRenderWidgetHost()->ForwardGestureEventWithLatencyInfo(
         scroll_begin, ui::LatencyInfo());
     // Scroll begin ignores ack disposition, so don't wait for the ack.
     WaitAFrame();
 
     // First touchmove already sent, start at 2.
     for (int i = 2; i <= 10; ++i) {
       // Send a touch move, followed by a scroll update
       touch.MovePoint(0, bounds.x() + 20 + i * dx, bounds.y() + 100);
       GetRenderWidgetHost()->ForwardTouchEventWithLatencyInfo(
@@ skipping 155 matching lines @@
     details = dispatcher->OnEventFromSource(&release);
     ASSERT_FALSE(details.dispatcher_destroyed);
     WaitAFrame();
 
     EXPECT_LT(0, tracker.num_overscroll_updates());
     EXPECT_FALSE(tracker.overscroll_completed());
   }
 }
 
 }  // namespace content