SF: Update InputFlinger outside main thread

Avoids parceling data inside  main thread and hot path. Also
avoids any binder contention with one way binder calls. See
bug for more details.

Bug: 206380307
Test: presubmit
Test: systrace
Change-Id: I4f8640587c821ac471559f1e6d2fbe41a8e64c87
diff --git a/libs/gui/LayerState.cpp b/libs/gui/LayerState.cpp
index f848e4f..bb7e1a4 100644
--- a/libs/gui/LayerState.cpp
+++ b/libs/gui/LayerState.cpp
@@ -546,9 +546,7 @@
 }
 
 bool InputWindowCommands::empty() const {
-    bool empty = true;
-    empty = focusRequests.empty() && !syncInputWindows;
-    return empty;
+    return focusRequests.empty() && !syncInputWindows;
 }
 
 void InputWindowCommands::clear() {