[DX] Layout Contexts not being passed to block in hook_block_view().

Describe your issue or idea

I'm trying to create some blocks for taxonomy term pages, but in all instances I'm unable to access the term from context. Here's my code:

/**
 * Implementation of hook_block_view().
 */
function customblocks_block_view($delta = '', $settings = array(), $contexts = array()) {
  dpm($contexts);
}

I've also tried adding this block onto a node/% layout as well as a user/% layout, with the same effect.

At first I was worried this may be related to https://github.com/backdrop/backdrop/pull/1906, but it looks like that PR does not affect the behavior of hook_block_view() but only it's _alter() counterpart.

Steps to reproduce (if reporting a bug)

• Create a custom module using the block hooks _info and _view
• Place the block on a node, user, or term layout.
• View the layout.

Actual behavior (if reporting a bug)

No contexts are available.

Expected behavior (if reporting a bug)

Contexts should be available.

Relevant version/system information (if applicable)

Backdrop 1.9