Remove ViewState

The only remaining usage of view state was to reset the number of files
shown everytime the patchrange/change changes but we can do that when
we collapse all file diffs in the change page.

With this change we got rid of all viewState. :D

Release-Notes: skip
Change-Id: I6e2f91dbaf5fffa497292baf7576e4c92217784a
diff --git a/polygerrit-ui/app/types/types.ts b/polygerrit-ui/app/types/types.ts
index 3763733..c7a5d14 100644
--- a/polygerrit-ui/app/types/types.ts
+++ b/polygerrit-ui/app/types/types.ts
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 import {DiffLayer as DiffLayerApi} from '../api/diff';
-import {DiffViewMode, MessageTag, Side} from '../constants/constants';
+import {MessageTag, Side} from '../constants/constants';
 import {IronA11yAnnouncer} from '@polymer/iron-a11y-announcer/iron-a11y-announcer';
 import {FlattenedNodesObserver} from '@polymer/polymer/lib/utils/flattened-nodes-observer';
 import {PaperInputElement} from '@polymer/paper-input/paper-input';
@@ -15,8 +15,6 @@
   CommitId,
   CommitInfo,
   EditPatchSet,
-  NumericChangeId,
-  PatchRange,
   PatchSetNum,
   ReviewerUpdateInfo,
   RevisionInfo,
@@ -172,15 +170,6 @@
   removeListener?(listener: DiffLayerListener): void;
 }
 
-export interface ChangeViewState {
-  changeNum: NumericChangeId | null;
-  patchRange: PatchRange | null;
-  diffMode: DiffViewMode | null;
-}
-export interface ViewState {
-  changeView: ChangeViewState;
-}
-
 export interface PatchSetFile {
   path: string;
   basePath?: string;