perfetto-ui: Plumb notifyEof from UI to WASM

Change-Id: Iaa1559148cee2c0488a40fae4cd4262d39873386
diff --git a/ui/src/controller/trace_controller.ts b/ui/src/controller/trace_controller.ts
index 9b85de6..49fabaf 100644
--- a/ui/src/controller/trace_controller.ts
+++ b/ui/src/controller/trace_controller.ts
@@ -159,6 +159,8 @@
       }
     }
 
+    await this.engine.notifyEof();
+
     const traceTime = await this.engine.getTraceTimeBounds();
     const actions = [
       setTraceTime(traceTime),