Reflects refactoring of JNI helper code that depends on private methods within libnativehelper. Bug: 151443957 Test: Treehugger Change-Id: I7af128f42ae89a77a8e3fb113ea533331153c535 Merged-In: I7af128f42ae89a77a8e3fb113ea533331153c535 Exempt-From-Owner-Approval: cherry pick (cherry picked from commit 329c612e3d5ae440bf13e1f5fc9a4012263524e9)