Extend the vocabulary of the `providedIn` to also include `'platform'` and `'any'`` scope.
```
@Injectable({
providedId: 'platform', // tree shakable injector for platform injector
})
class MyService {...}
```
PR Close#32154
This change is a prerequasity for a later change which will turn the
'di' into its own bazel package. In order to do that we have to:
- have `Injector` type be importable by Ivy. This means that we need
to create `Injector` as a pure type in `interface` folder which is
already a bazel package which Ivy can depend on.
- Remove the dependency of `class Injector` on Ivy so that it can be
compiled in isolation. We do that by using `-1` as special value for
`__NG_ELEMENT_ID__` which tells the Ivy `NodeInjector` than
`Injector` is being requested.
PR Close#28066
Rename @Injectable({scope -> providedIn}).
Instead of {providedIn: APP_ROOT_SCOPE}, accept {providedIn: 'root'}.
Also, {providedIn: null} implies the injectable should not be added
to any scope.
PR Close#22655
@Injectable() supports a scope parameter which specifies the target module.
However, it's still difficult to specify that a particular service belongs
in the root injector. A developer attempting to ensure that must either
also provide a module intended for placement in the root injector or target
a module known to already be in the root injector (e.g. BrowserModule).
Both of these strategies are cumbersome and brittle.
Instead, this commit adds a token APP_ROOT_SCOPE which provides a
straightforward way of targeting the root injector directly, without
requiring special knowledge of modules within it.
PR Close#22185
