Adding JNI code for dalvik.system.DexFile and java.lang.Class

Change-Id: I079c037db77aeaca0dec06660f7551f57adf2607
diff --git a/src/utils.h b/src/utils.h
index e582c7d..97bf2c8 100644
--- a/src/utils.h
+++ b/src/utils.h
@@ -172,6 +172,9 @@
 // of the JNI spec.
 std::string MangleForJni(const std::string& s);
 
+// Turn "java.lang.String" into "Ljava/lang/String;".
+std::string DotToDescriptor(const char* class_name);
+
 // Tests whether 's' is a valid class name.
 // name_or_descriptor
 //     true  => "java/lang/String"