Move KeyCharacterMap from RefBase to shared_ptr.

Move KeyCharacterMap from RefBase and make it shared_ptr in EventHub
device when loaded from file.
A shared_ptr of KeyCharacterMap is returned by EventHub getKeyCharacterMap
to be shared in InputdeviceInfo.
Remove extra KeyCharacterMap in EventHub to save memory sapce.

Bug: 160010896
Test: atest inputflinger, atest libinput_tests

Change-Id: Ibb317ea0684e6af6e7a6d808f816fc4a05c7b421
diff --git a/include/input/Keyboard.h b/include/input/Keyboard.h
index 4c56a69..2ae4fd5 100644
--- a/include/input/Keyboard.h
+++ b/include/input/Keyboard.h
@@ -37,7 +37,7 @@
     std::shared_ptr<KeyLayoutMap> keyLayoutMap;
 
     std::string keyCharacterMapFile;
-    sp<KeyCharacterMap> keyCharacterMap;
+    std::shared_ptr<KeyCharacterMap> keyCharacterMap;
 
     KeyMap();
     ~KeyMap();