Revert of Remove enable/disable wheel gestures setting.

content/browser/renderer_host/input/mouse_wheel_event_queue.cc

 // Copyright 2016 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/renderer_host/input/mouse_wheel_event_queue.h"
 
 #include "base/metrics/histogram_macros.h"
 #include "base/stl_util.h"
 #include "base/trace_event/trace_event.h"
 
@@ skipping 15 matching lines @@
 
   ~QueuedWebMouseWheelEvent() {
     TRACE_EVENT_ASYNC_END0("input", "MouseWheelEventQueue::QueueEvent", this);
   }
 
  private:
   DISALLOW_COPY_AND_ASSIGN(QueuedWebMouseWheelEvent);
 };
 
 MouseWheelEventQueue::MouseWheelEventQueue(MouseWheelEventQueueClient* client,
+                                           bool send_gestures,
                                            int64_t scroll_transaction_ms)
     : client_(client),
       needs_scroll_begin_(true),
       needs_scroll_end_(false),
+      send_gestures_(send_gestures),
       scroll_transaction_ms_(scroll_transaction_ms),
       scrolling_device_(blink::WebGestureDeviceUninitialized) {
   DCHECK(client);
 }
 
 MouseWheelEventQueue::~MouseWheelEventQueue() {
   if (!wheel_queue_.empty())
     STLDeleteElements(&wheel_queue_);
 }
 
@@ skipping 22 matching lines @@
     InputEventAckState ack_result,
     const LatencyInfo& latency_info) {
   TRACE_EVENT0("input", "MouseWheelEventQueue::ProcessMouseWheelAck");
   if (!event_sent_for_gesture_ack_)
     return;
 
   event_sent_for_gesture_ack_->latency.AddNewLatencyFrom(latency_info);
   client_->OnMouseWheelEventAck(*event_sent_for_gesture_ack_, ack_result);
 
   // If event wasn't consumed then generate a gesture scroll for it.
-  if (ack_result != INPUT_EVENT_ACK_STATE_CONSUMED &&
+  if (send_gestures_ && ack_result != INPUT_EVENT_ACK_STATE_CONSUMED &&
       event_sent_for_gesture_ack_->event.canScroll &&
       event_sent_for_gesture_ack_->event.resendingPluginId == -1 &&
       (scrolling_device_ == blink::WebGestureDeviceUninitialized ||
        scrolling_device_ == blink::WebGestureDeviceTouchpad)) {
     WebGestureEvent scroll_update;
     scroll_update.timeStampSeconds =
         event_sent_for_gesture_ack_->event.timeStampSeconds;
 
     scroll_update.x = event_sent_for_gesture_ack_->event.x;
     scroll_update.y = event_sent_for_gesture_ack_->event.y;
@@ skipping 190 matching lines @@
   scroll_begin.data.scrollBegin.targetViewport = false;
   scroll_begin.data.scrollBegin.deltaHintUnits =
       gesture_update.data.scrollUpdate.deltaUnits;
 
   needs_scroll_begin_ = false;
   needs_scroll_end_ = true;
   client_->ForwardGestureEventWithLatencyInfo(scroll_begin, ui::LatencyInfo());
 }
 
 }  // namespace content