Bug 1440740 - Calling PropTypes validators directly is not supported when first opening Memory Tool r=nchevobbe

Fix eslint errors (unused vars)

MozReview-Commit-ID: IunuZlHIY1S

--HG--
extra : rebase_source : c8fa47d55f4454d6330a375356dff2ac1d7aef26

devtools/client/memory/models.js

@@ -382,7 +382,7 @@ let previousViewModel = exports.previousView = PropTypes.shape({
   selected: snapshotId,
 });
 
-let viewModel = exports.view = PropTypes.shape({
+exports.view = PropTypes.shape({
   // The current view state.
   state: catchAndIgnore(function (view) {
     switch (view.state) {
@@ -486,8 +486,6 @@ exports.app = {
 
   // The current type of view.
   view: function (app) {
-    viewModel.isRequired(app, "view");
-
     catchAndIgnore(function (app) {
       switch (app.view.state) {
         case viewState.DIFFING: