Merge changes from topics \'cam-ndk-hidden-enum\', \'cam-ndk-enum-dco\', \'cam-ndk-hidden-keys\' into nyc-dev
am: b1379bd

* commit 'b1379bdb8fe4ddf1e052bff5e76703f70ec4afab':
  Camera: hide some enum values in NDK
  Camera: codegen NDK metadata enum value documents
  Camera: modify metadata visibility attributes

Change-Id: Ife5a241f013a3f4bac5b41fc2b358005c8cb6a7b