Add API to get KeyCode produced by physical key location.

The physical key location is provided as a location KeyCode pointing to a location on a US keyboard layout.

Bug: 179812917
Test: atest KeyboardLayoutChangeTest
Test: atest android.hardware.input.cts.tests -m
Test: atest inputflinger_tests -m
Change-Id: Ib5ed41890cbbe393ee9ada1a04cbaaf82c9bb1fc
diff --git a/services/inputflinger/reader/mapper/SwitchInputMapper.h b/services/inputflinger/reader/mapper/SwitchInputMapper.h
index 4d74163..64b9aa2 100644
--- a/services/inputflinger/reader/mapper/SwitchInputMapper.h
+++ b/services/inputflinger/reader/mapper/SwitchInputMapper.h
@@ -26,7 +26,7 @@
     explicit SwitchInputMapper(InputDeviceContext& deviceContext);
     virtual ~SwitchInputMapper();
 
-    virtual uint32_t getSources() override;
+    virtual uint32_t getSources() const override;
     virtual void process(const RawEvent* rawEvent) override;
 
     virtual int32_t getSwitchState(uint32_t sourceMask, int32_t switchCode) override;