[ART] Move to system/core native bridge library

Some cleanups on the way:
- move NativeBridgeRuntimeCallbacks from a global to a field
- rename native_bridge_library_string to the more suggestive
navtive_bridge_library_path
- clean up imports

Bug: 16884833
Change-Id: I73aab8e212860ba5aee9444d801806d3da326a41
diff --git a/runtime/parsed_options.h b/runtime/parsed_options.h
index c328ca7..7955c89 100644
--- a/runtime/parsed_options.h
+++ b/runtime/parsed_options.h
@@ -46,7 +46,7 @@
   bool check_jni_;
   bool force_copy_;
   std::string jni_trace_;
-  std::string native_bridge_library_string_;
+  std::string native_bridge_library_path_;
   CompilerCallbacks* compiler_callbacks_;
   bool is_zygote_;
   bool must_relocate_;