Fixes regarding to comments in ag/2839267

1. use struct {} to instantiate privacy fields for efficiency reason
2. use vector<uint8_t>* instead of vector<uint8_t>& to indicate the
caller knows the value gets changed.
3. binary search privay policy for sections

Bug: 65595927
Test: unit test covers
Change-Id: Ic58c2f607465d1a7f10352b9a38c3d8b1a5cf352