Add knowledge about blocking and passive event listeners.

cc/layers/layer_impl.cc

 // Copyright 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 "cc/layers/layer_impl.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <utility>
@@ skipping 527 matching lines @@
           MainThreadScrollingReason::kNonFastScrollableRegion;
       return scroll_status;
     }
   }
 
   if (type == InputHandler::WHEEL || type == InputHandler::ANIMATED_WHEEL) {
     EventListenerProperties event_properties =
         layer_tree_impl_->event_listener_properties(
             EventListenerClass::kMouseWheel);
     if (event_properties == EventListenerProperties::kBlocking ||
+        event_properties == EventListenerProperties::kBlockingAndPassive ||
         (!layer_tree_impl_->settings().use_mouse_wheel_gestures &&
          event_properties == EventListenerProperties::kPassive)) {
       TRACE_EVENT0("cc", "LayerImpl::tryScroll: Failed WheelEventHandlers");
       scroll_status.thread = InputHandler::SCROLL_ON_MAIN_THREAD;
       scroll_status.main_thread_scrolling_reasons =
           MainThreadScrollingReason::kEventHandlers;
       return scroll_status;
     }
   }
 
@@ skipping 1344 matching lines @@
            .layer_transforms_should_scale_layer_contents) {
     return default_scale;
   }
 
   gfx::Vector2dF transform_scales = MathUtil::ComputeTransform2dScaleComponents(
       DrawTransform(), default_scale);
   return std::max(transform_scales.x(), transform_scales.y());
 }
 
 }  // namespace cc