Stamp platform version code into app Apks

The versionCode of theframework resources that an app is built against
gets stamped inside an app's AndroidManifest.xml in the <manifest>
tag as "platformBuildVersionCode" and "platformBuildVersionName"
attributes.

Bug:17207635
Change-Id: Id573c3dffcbca38eec9c0eb3e89f4a547e3361d3
diff --git a/include/androidfw/ResourceTypes.h b/include/androidfw/ResourceTypes.h
index 11568d2..c65efe4 100644
--- a/include/androidfw/ResourceTypes.h
+++ b/include/androidfw/ResourceTypes.h
@@ -1557,7 +1557,7 @@
     };
     const char16_t* valueToString(const Res_value* value, size_t stringBlock,
                                   char16_t tmpBuffer[TMP_BUFFER_SIZE],
-                                  size_t* outLen);
+                                  size_t* outLen) const;
 
     struct bag_entry {
         ssize_t stringBlock;