Plumb firing passive event listeners.

content/renderer/input/input_handler_manager.cc

Index: content/renderer/input/input_handler_manager.cc
diff --git a/content/renderer/input/input_handler_manager.cc b/content/renderer/input/input_handler_manager.cc
index 35ef3b467334d110476a60839acff8a87f27162a..9e42b482d294e2f917a4f89701045a299f45b81a 100644
--- a/content/renderer/input/input_handler_manager.cc
+++ b/content/renderer/input/input_handler_manager.cc
@@ -36,6 +36,8 @@ InputEventAckState InputEventDispositionToAck(
       return INPUT_EVENT_ACK_STATE_NOT_CONSUMED;
     case InputHandlerProxy::DROP_EVENT:
       return INPUT_EVENT_ACK_STATE_NO_CONSUMER_EXISTS;
+    case InputHandlerProxy::NON_BLOCKING:
+      return INPUT_EVENT_ACK_STATE_SET_NON_BLOCKING;
   }
   NOTREACHED();
   return INPUT_EVENT_ACK_STATE_UNKNOWN;
@@ -141,6 +143,27 @@ void InputHandlerManager::ObserveWheelEventAndResultOnCompositorThread(
       wheel_event, scroll_result);
 }
 
+void InputHandlerManager::NonBlockingInputEventHandledOnMainThread(
+    int routing_id,
+    blink::WebInputEvent::Type type) {

[tdresser, 2016/02/08 17:51:32]

Does it make sense to:
DCHECK(!task_runner_->BelongsToCurrentThread());

[dtapuska, 2016/02/09 19:40:11]

There is no check in the ObserveWheelEventAndResultOnMainThread method; and it
only accesses the task_runner_ to post the task which all should be thread safe.
So I'm not sure it warrants a DCHECK.

+  task_runner_->PostTask(
+      FROM_HERE,
+      base::Bind(
+          &InputHandlerManager::NonBlockingInputEventHandledOnCompositorThread,
+          base::Unretained(this), routing_id, type));
+}
+
+void InputHandlerManager::NonBlockingInputEventHandledOnCompositorThread(
+    int routing_id,
+    blink::WebInputEvent::Type handled_type) {
+  DCHECK(task_runner_->BelongsToCurrentThread());
+  auto it = input_handlers_.find(routing_id);
+  if (it == input_handlers_.end())
+    return;
+
+  client_->NonBlockingInputEventHandled(routing_id, handled_type);
+}
+
 InputEventAckState InputHandlerManager::HandleInputEvent(
     int routing_id,
     const WebInputEvent* input_event,