Handle touchpad flings with passive event listeners on compositor 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 477def4d78180891f37c6d90022de881114aad95..1222d6ca88a2593477887c3ee18e3b967942fe65 100644
--- a/content/renderer/input/input_handler_manager.cc
+++ b/content/renderer/input/input_handler_manager.cc
@@ -248,4 +248,13 @@ void InputHandlerManager::DidAnimateForInput() {
   renderer_scheduler_->DidAnimateForInputOnCompositorThread();
 }
 
+void InputHandlerManager::DispatchNonBlockingEventToMainThread(
+    int routing_id,
+    ui::ScopedWebInputEvent event,
+    const ui::LatencyInfo& latency_info) {
+  DCHECK(task_runner_->BelongsToCurrentThread());
+  client_->DispatchNonBlockingEventToMainThread(routing_id, std::move(event),
+                                                latency_info);
+}
+
 }  // namespace content