Refactor VirtualKeyMap

Currently, there's a lot of new and delete going on in VirtualKeyMap.
Simplify this by using unique_ptr instead.

Bug: 113575658
Test: atest libinput_tests inputflinger_tests
Change-Id: Ib2a68ae23a4300b0e2cf72902371f4b9604cfee5
diff --git a/include/input/VirtualKeyMap.h b/include/input/VirtualKeyMap.h
index 24e0e0e..4f7cfb6 100644
--- a/include/input/VirtualKeyMap.h
+++ b/include/input/VirtualKeyMap.h
@@ -49,7 +49,7 @@
 public:
     ~VirtualKeyMap();
 
-    static status_t load(const std::string& filename, VirtualKeyMap** outMap);
+    static std::unique_ptr<VirtualKeyMap> load(const std::string& filename);
 
     inline const Vector<VirtualKeyDefinition>& getVirtualKeys() const {
         return mVirtualKeys;