InputTracer: Trace an event being dispatched to a window

Bug: 210460522
Test: manual with perfetto
Change-Id: Ie161726da294bc5c660d5062af85c9cd621c1b4c
diff --git a/services/inputflinger/dispatcher/trace/InputTracingPerfettoBackend.cpp b/services/inputflinger/dispatcher/trace/InputTracingPerfettoBackend.cpp
index db88726..4442ad8 100644
--- a/services/inputflinger/dispatcher/trace/InputTracingPerfettoBackend.cpp
+++ b/services/inputflinger/dispatcher/trace/InputTracingPerfettoBackend.cpp
@@ -81,8 +81,14 @@
     });
 }
 
-void PerfettoBackend::traceWindowDispatch(const WindowDispatchArgs&) const {
-    // TODO(b/210460522): Implement.
+void PerfettoBackend::traceWindowDispatch(const WindowDispatchArgs& dispatchArgs) const {
+    InputEventDataSource::Trace([&](InputEventDataSource::TraceContext ctx) {
+        auto tracePacket = ctx.NewTracePacket();
+        auto* inputEventProto = tracePacket->set_android_input_event();
+        auto* dispatchEventProto = inputEventProto->set_dispatcher_window_dispatch_event();
+        AndroidInputEventProtoConverter::toProtoWindowDispatchEvent(dispatchArgs,
+                                                                    *dispatchEventProto);
+    });
 }
 
 } // namespace android::inputdispatcher::trace::impl