Add setFocusedWindow function stub

This function, once implemented, will set focus on the specified
window. This is the first step in changing focus selection from
setInputWindows and using explicit call which will help us more
easily decouple z-order from focus selection and support focus
for SurfaceViewHost surfaces.

Bug: 151179149
Test: presubmit
Test: go/wm-smoke
Test: atest inputflinger_tests

Change-Id: Ib2254b4ab3ba8d579dfe49ddf3286f8ce2eecf9e
diff --git a/services/inputflinger/InputManager.cpp b/services/inputflinger/InputManager.cpp
index 088c6f1..e49667e 100644
--- a/services/inputflinger/InputManager.cpp
+++ b/services/inputflinger/InputManager.cpp
@@ -146,4 +146,9 @@
     return NO_ERROR;
 }
 
+binder::Status InputManager::setFocusedWindow(const FocusRequest& request) {
+    mDispatcher->setFocusedWindow(request);
+    return binder::Status::ok();
+}
+
 } // namespace android