libandroidfw: move ConfigDescription from aapt2 to libandroidfw

This is to allow idmap2 to access ConfigDescription.

Test: libandroidfw_tests
Test: aapt2_tests
Change-Id: I54210bbbd8dad5903cb7100807df977efa394ad5
diff --git a/tools/aapt2/optimize/VersionCollapser.cpp b/tools/aapt2/optimize/VersionCollapser.cpp
index cc1fc1e..f985604 100644
--- a/tools/aapt2/optimize/VersionCollapser.cpp
+++ b/tools/aapt2/optimize/VersionCollapser.cpp
@@ -21,6 +21,8 @@
 
 #include "ResourceTable.h"
 
+using android::ConfigDescription;
+
 namespace aapt {
 
 template <typename Iterator, typename Pred>