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/SingleTouchInputMapper.h b/services/inputflinger/reader/mapper/SingleTouchInputMapper.h
index 7726bfb..bc38711 100644
--- a/services/inputflinger/reader/mapper/SingleTouchInputMapper.h
+++ b/services/inputflinger/reader/mapper/SingleTouchInputMapper.h
@@ -31,7 +31,7 @@
     ~SingleTouchInputMapper() override;
 
     [[nodiscard]] std::list<NotifyArgs> reset(nsecs_t when) override;
-    [[nodiscard]] std::list<NotifyArgs> process(const RawEvent* rawEvent) override;
+    [[nodiscard]] std::list<NotifyArgs> process(const RawEvent& rawEvent) override;
 
 protected:
     void syncTouch(nsecs_t when, RawState* outState) override;