Add function definitions for MapInfo.

Bug: 23762183

Test: All new unit tests pass.
Change-Id: I26a1f6e84bf1a02447eff48ff6e35068554330fe
diff --git a/libunwindstack/MapInfo.h b/libunwindstack/MapInfo.h
index 8342904..79a2ada 100644
--- a/libunwindstack/MapInfo.h
+++ b/libunwindstack/MapInfo.h
@@ -39,6 +39,7 @@
   uint64_t elf_offset;
 
   Memory* CreateMemory(pid_t pid);
+  Elf* GetElf(pid_t pid, bool init_gnu_debugdata = false);
 };
 
 #endif  // _LIBUNWINDSTACK_MAP_INFO_H