Bugzilla

Flow currently has "inexact" and "exact" object types, where exact objects must have _exactly_ the fields given in the type, and inexact objects must have those fields, but are also allowed to have additional properties. 

The common syntax is
```
type SomeExactObj = {| prop: string |};
type SomeInexactObj = { prop: string };
```
but in fact, the Flow team eventually wants to make `{ prop: string }` exact by default. (https://medium.com/flow-type/on-the-roadmap-exact-objects-by-default-16b72933c5cf) Along the path to this eventual goal, they have added a new "..." token to mark an object inexact:
```
type SomeInexactObj = { prop: string, ... };
```

We should update our codebase to require `...` for all types that aren't exact. That should mean

1. Enabling https://github.com/gajus/eslint-plugin-flowtype#eslint-plugin-flowtype-rules-require-inexact-type
2. Fixing all of the places in the codebase that are inexact but don't have `...`

Flow currently has "inexact" and "exact" object types, where exact objects must have _exactly_ the fields given in the type, and inexact objects must have those fields, but are also allowed to have additional properties. 

The common syntax is
```
type SomeExactObj = {| prop: string |};
type SomeInexactObj = { prop: string };
```
but in fact, the Flow team eventually wants to make `{ prop: string }` exact by default. (https://medium.com/flow-type/on-the-roadmap-exact-objects-by-default-16b72933c5cf) Along the path to this eventual goal, they have added a new "..." token to mark an object inexact:
```
type SomeInexactObj = { prop: string, ... };
```

We should update our codebase to require `...` for all types that aren't exact. That should mean

1. Enabling https://github.com/gajus/eslint-plugin-flowtype#eslint-plugin-flowtype-rules-require-inexact-type
2. Fixing all of the places in the codebase that are inexact but don't have `...`

I would recommend approaching this bug with a few steps
1. Figure out what we need to do to enable `eslint-plugin-flowtype` in `mozilla-central`, since right now it is not an ESLint plugin that we load.
2. Instead of manually fixing every instance of an inexact object, use this as motivation to submit a patch to `eslint-plugin-flowtype` to use ESlint's autofix framework to fix all the issues _for_ you, that way you can run ESLint with `--fix` to update all the debugger code.
3. Submit a patch adding `...` everywhere.