Communicate whether passive event listeners exist to cc.

cc/trees/layer_tree_host_impl_unittest.cc

Index: cc/trees/layer_tree_host_impl_unittest.cc
diff --git a/cc/trees/layer_tree_host_impl_unittest.cc b/cc/trees/layer_tree_host_impl_unittest.cc
index 9ea8484324c2820d75b1780db35fd331783c7f36..229f0d071e767a1cf82107ec00cbbae17512c704 100644
--- a/cc/trees/layer_tree_host_impl_unittest.cc
+++ b/cc/trees/layer_tree_host_impl_unittest.cc
@@ -717,7 +717,8 @@ TEST_F(LayerTreeHostImplTest, ScrollBlocksOnWheelEventHandlers) {
 
   // With registered event handlers, wheel scrolls don't necessarily
   // have to go to the main thread.
-  host_impl_->active_tree()->set_have_wheel_event_handlers(true);
+  host_impl_->active_tree()->set_event_listener_properties(
+      EventListenerClass::kMouseWheel, EventListenerProperties::kBlocking);
   InputHandler::ScrollStatus status =
     host_impl_->ScrollBegin(BeginState(gfx::Point()).get(),
                                    InputHandler::WHEEL);
@@ -735,7 +736,8 @@ TEST_F(LayerTreeHostImplTest, ScrollBlocksOnWheelEventHandlers) {
 
   // And if the handlers go away, wheel scrolls can again be processed
   // on impl (despite the scroll-blocks-on mode).

[Rick Byers, 2016/02/04 22:18:57]

Looks like we missed updating the comment and test name when you removed
scroll-blocks-on.  I think the one above (L718) is probably also stale.  This
test probably should be renamed / reworked to be testing passive vs. active vs.
nothing wheel listener behavior.  But maybe you want to do that in your next CL
instead and just leave it confusing for now?

-  host_impl_->active_tree()->set_have_wheel_event_handlers(false);
+  host_impl_->active_tree()->set_event_listener_properties(
+      EventListenerClass::kMouseWheel, EventListenerProperties::kNone);
   status = host_impl_->ScrollBegin(BeginState(gfx::Point()).get(),
                                    InputHandler::WHEEL);
   EXPECT_EQ(InputHandler::SCROLL_ON_IMPL_THREAD, status.thread);