Handle touchpad flings with passive event listeners on compositor thread.

blimp/client/core/input/blimp_input_handler_wrapper.cc

Index: blimp/client/core/input/blimp_input_handler_wrapper.cc
diff --git a/blimp/client/core/input/blimp_input_handler_wrapper.cc b/blimp/client/core/input/blimp_input_handler_wrapper.cc
index 8ed17f9b29b72282a3601d98206f445c20f57112..33ecdf31bef76657da6d47c6a4fc258a238cebd0 100644
--- a/blimp/client/core/input/blimp_input_handler_wrapper.cc
+++ b/blimp/client/core/input/blimp_input_handler_wrapper.cc
@@ -93,6 +93,16 @@ void BlimpInputHandlerWrapper::TransferActiveWheelFlingAnimation(
       << "Transferring Fling Animations to the engine is not supported";
 }
 
+void BlimpInputHandlerWrapper::DispatchNonBlockingEventToMainThread(
+    ui::ScopedWebInputEvent event,
+    const ui::LatencyInfo& latency_info) {
+  DCHECK(compositor_thread_checker_.CalledOnValidThread());
+  DCHECK_EQ(event->type, blink::WebInputEvent::MouseWheel);
+
+  NOTIMPLEMENTED()
+      << "Dispatching Non Blocking Events to the engine is not supported";
+}
+
 blink::WebGestureCurve* BlimpInputHandlerWrapper::CreateFlingAnimationCurve(
     blink::WebGestureDevice device_source,
     const blink::WebFloatPoint& velocity,