Bug 1479515 - Add an ESLint rule to check for unknown property accesses on Ci. r=Gijs

This is manually run and requires a full build. MOZ_OBJDIR needs to be set to point to the object directory.

Differential Revision: https://phabricator.services.mozilla.com/D156424

docs/code-quality/lint/linters/eslint-plugin-mozilla.rst

@@ -72,6 +72,7 @@ The plugin implements the following rules:
    eslint-plugin-mozilla/use-ownerGlobal
    eslint-plugin-mozilla/use-returnValue
    eslint-plugin-mozilla/use-services
+   eslint-plugin-mozilla/valid-ci-uses
    eslint-plugin-mozilla/valid-lazy
    eslint-plugin-mozilla/var-only-at-top-level
 

docs/code-quality/lint/linters/eslint-plugin-mozilla/valid-ci-uses.rst

@@ -0,0 +1,29 @@
+valid-ci-uses
+=============
+
+Ensures that property access on ``Ci.<interface>`` are valid.
+
+This rule requires a full build to run, and is not turned on by default. To run
+this rule manually, use:
+
+.. code-block:: console
+
+    MOZ_OBJDIR=objdir-ff-opt ./mach eslint --rule="mozilla/valid-ci-uses: error" *
+
+Examples of incorrect code for this rule:
+-----------------------------------------
+
+``UNKNOWN_CONSTANT`` does not exist on nsIURIFixup.
+
+.. code-block:: js
+
+    Ci.nsIURIFixup.UNKNOWN_CONSTANT
+
+Examples of correct code for this rule:
+---------------------------------------
+
+``FIXUP_FLAG_NONE`` does exist on nsIURIFixup.
+
+.. code-block:: js
+
+    Ci.nsIURIFixup.FIXUP_FLAG_NONE