Don't use PostTask queueing between compositor and main thread.

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 0821d8225fcbf5446f1a42d2b0068413ff4a3577..99a22ca264055249a8ff7880a4dbba27c0e4bd74 100644
--- a/content/renderer/input/input_handler_manager.cc
+++ b/content/renderer/input/input_handler_manager.cc
@@ -189,23 +189,7 @@ void InputHandlerManager::NotifyInputEventHandledOnMainThread(
     int routing_id,
     blink::WebInputEvent::Type type,
     InputEventAckState ack_result) {
-  task_runner_->PostTask(
-      FROM_HERE,
-      base::Bind(
-          &InputHandlerManager::NotifyInputEventHandledOnCompositorThread,
-          base::Unretained(this), routing_id, type, ack_result));
-}
-
-void InputHandlerManager::NotifyInputEventHandledOnCompositorThread(
-    int routing_id,
-    blink::WebInputEvent::Type handled_type,
-    InputEventAckState ack_result) {
-  DCHECK(task_runner_->BelongsToCurrentThread());
-  auto it = input_handlers_.find(routing_id);
-  if (it == input_handlers_.end())
-    return;
-
-  client_->NotifyInputEventHandled(routing_id, handled_type, ack_result);
+  client_->NotifyInputEventHandled(routing_id, type, ack_result);
 }
 
 InputEventAckState InputHandlerManager::HandleInputEvent(