These are almost only doc changes, with two exceptions:
1-In LinkHolderArray, int-alike array keys are now cast to int, to be uniform with what we do in other code paths
2-In ExtensionRegistration, changed a line to throw an Exception
immediately, instead of an ExtensionDependencyError. This is because the
latter takes an array with msg and type, but we were passing it a plain
string (and in fact the code was bugged).
Bug: T231636
Change-Id: I8b0ef50d279c2a87490dde6a467a4e22c0710afd
Needed for selective updates of pages using a particular feature.
Intended to be run in production, so needs to scale.
Bug: T149723
Change-Id: If20fb1f91de8d4227def5b07d6d52b91161ed3fd
