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/libs/gui/SurfaceComposerClient.cpp b/libs/gui/SurfaceComposerClient.cpp
index d797a35..229a5c2 100644
--- a/libs/gui/SurfaceComposerClient.cpp
+++ b/libs/gui/SurfaceComposerClient.cpp
@@ -1364,6 +1364,21 @@
     return *this;
 }
 
+SurfaceComposerClient::Transaction& SurfaceComposerClient::Transaction::setFocusedWindow(
+        const sp<IBinder>& token, const sp<IBinder>& focusedToken, nsecs_t timestampNanos) {
+    FocusRequest request;
+    request.token = token;
+    request.focusedToken = focusedToken;
+    request.timestamp = timestampNanos;
+    return setFocusedWindow(request);
+}
+
+SurfaceComposerClient::Transaction& SurfaceComposerClient::Transaction::setFocusedWindow(
+        const FocusRequest& request) {
+    mInputWindowCommands.focusRequests.push_back(request);
+    return *this;
+}
+
 SurfaceComposerClient::Transaction& SurfaceComposerClient::Transaction::syncInputWindows() {
     mInputWindowCommands.syncInputWindows = true;
     return *this;