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/SwitchInputMapper.h b/services/inputflinger/reader/mapper/SwitchInputMapper.h
index 2fb48bb..5d8aa2c 100644
--- a/services/inputflinger/reader/mapper/SwitchInputMapper.h
+++ b/services/inputflinger/reader/mapper/SwitchInputMapper.h
@@ -29,7 +29,7 @@
     virtual ~SwitchInputMapper();
 
     virtual uint32_t getSources() const override;
-    [[nodiscard]] std::list<NotifyArgs> process(const RawEvent* rawEvent) override;
+    [[nodiscard]] std::list<NotifyArgs> process(const RawEvent& rawEvent) override;
 
     virtual int32_t getSwitchState(uint32_t sourceMask, int32_t switchCode) override;
     virtual void dump(std::string& dump) override;