Clean up InputDispatcherPolicyInterface

- Remove RefBase from policy
- Store reference instead of pointer to policy
- Use references instead of pointers in parameters
- Use return values for all outputs for functions instead of passing an
  out parameter

Bug: 279927189
Bug: 245989146
Test: Presubmit
Change-Id: I31a2a3e8c67960020169ddfc59bc0a59f3e65c52
diff --git a/services/inputflinger/dispatcher/InputDispatcherFactory.cpp b/services/inputflinger/dispatcher/InputDispatcherFactory.cpp
index bca1600..3ef8419 100644
--- a/services/inputflinger/dispatcher/InputDispatcherFactory.cpp
+++ b/services/inputflinger/dispatcher/InputDispatcherFactory.cpp
@@ -20,7 +20,7 @@
 namespace android {
 
 std::unique_ptr<InputDispatcherInterface> createInputDispatcher(
-        const sp<InputDispatcherPolicyInterface>& policy) {
+        InputDispatcherPolicyInterface& policy) {
     return std::make_unique<android::inputdispatcher::InputDispatcher>(policy);
 }