InputMapper: pass RawEvent references instead of pointers

We never pass null values here, so changing to references makes this
clearer.

Change-Id: I82d5359e244a93560bcbef477c89fef016168abb
Test: atest inputflinger_test
Test: m checkinput
Test: manually test basic functionality on a multi-touch screen, touchpad, mouse, and drawing tablet
Bug: 245989146
Flag: EXEMPT refactor
diff --git a/services/inputflinger/reader/mapper/InputMapper.h b/services/inputflinger/reader/mapper/InputMapper.h
index c7eea0e..2c51448 100644
--- a/services/inputflinger/reader/mapper/InputMapper.h
+++ b/services/inputflinger/reader/mapper/InputMapper.h
@@ -78,7 +78,7 @@
                                                             const InputReaderConfiguration& config,
                                                             ConfigurationChanges changes);
     [[nodiscard]] virtual std::list<NotifyArgs> reset(nsecs_t when);
-    [[nodiscard]] virtual std::list<NotifyArgs> process(const RawEvent* rawEvent) = 0;
+    [[nodiscard]] virtual std::list<NotifyArgs> process(const RawEvent& rawEvent) = 0;
     [[nodiscard]] virtual std::list<NotifyArgs> timeoutExpired(nsecs_t when);
 
     virtual int32_t getKeyCodeState(uint32_t sourceMask, int32_t keyCode);