This change adds in the following new lifecycle hooks, which map in some
way to those in Angular 2:
* `$onChanges(changesObj)` - Called whenever one-way bindings are updated. The `changesObj` is a hash whose keys
are the names of the bound properties that have changed, and the values are an object of the form
`{ currentValue: ..., previousValue: ... }`. Use this hook to trigger updates within a component such as
cloning the bound value to prevent accidental mutation of the outer value.
* `$onDestroy` - Called on a controller when its containing scope is destroyed. Use this hook for releasing
external resources, watches and event handlers.
* `$postLink` - Called after this controller's element and its children been linked. Similar to the post-link
function this hook can be used to set up DOM event handlers and do direct DOM manipulation.
Note that child elements that contain `templateUrl` directives will not have been compiled and linked since
they are waiting for their template to load asynchronously and their own compilation and linking has been
suspended until that occurs.
Closes#14127Closes#14030Closes#14020Closes#13991Closes#14302
Peter Bacon Darwin
874c0fdcdd