Remove RefBase from InputListener interface

We don't need refbase for inputlisteners. Remove it, and switch to
references, which cannot be null. This way, we can avoid dereferencing
the pointers without checking for nullness.

Bug: 198472780
Test: atest inputflinger_tests
Change-Id: I2f469fd268472c7e78d36812353cff5c52a90163
diff --git a/services/inputflinger/include/InputReaderFactory.h b/services/inputflinger/include/InputReaderFactory.h
index 9db6233..dad14d6 100644
--- a/services/inputflinger/include/InputReaderFactory.h
+++ b/services/inputflinger/include/InputReaderFactory.h
@@ -22,8 +22,7 @@
 class InputReaderPolicyInterface;
 class InputListenerInterface;
 
-sp<InputReaderInterface> createInputReader(
-        const sp<InputReaderPolicyInterface>& policy,
-        const sp<InputListenerInterface>& listener);
+std::unique_ptr<InputReaderInterface> createInputReader(
+        const sp<InputReaderPolicyInterface>& policy, InputListenerInterface& listener);
 
 } // namespace android