Merge "Revert "Retire the token highlight experiment""
diff --git a/polygerrit-ui/app/elements/diff/gr-apply-fix-dialog/gr-apply-fix-dialog.ts b/polygerrit-ui/app/elements/diff/gr-apply-fix-dialog/gr-apply-fix-dialog.ts
index 1908df0..6dd67e4 100644
--- a/polygerrit-ui/app/elements/diff/gr-apply-fix-dialog/gr-apply-fix-dialog.ts
+++ b/polygerrit-ui/app/elements/diff/gr-apply-fix-dialog/gr-apply-fix-dialog.ts
@@ -41,6 +41,7 @@
 import {ParsedChangeInfo} from '../../../types/types';
 import {GrButton} from '../../shared/gr-button/gr-button';
 import {TokenHighlightLayer} from '../gr-diff-builder/token-highlight-layer';
+import {KnownExperimentId} from '../../../services/flags/flags';
 
 export interface GrApplyFixDialog {
   $: {
@@ -98,7 +99,11 @@
   })
   _disableApplyFixButton = false;
 
-  layers = [new TokenHighlightLayer(this)];
+  layers = appContext.flagsService.isEnabled(
+    KnownExperimentId.TOKEN_HIGHLIGHTING
+  )
+    ? [new TokenHighlightLayer(this)]
+    : [];
 
   private refitOverlay?: () => void;
 
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host.ts b/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host.ts
index fa3ddf4..c4fed53 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host.ts
@@ -412,7 +412,11 @@
 
   private _getLayers(path: string): DiffLayer[] {
     const layers = [];
-    layers.push(new TokenHighlightLayer(this));
+    if (
+      appContext.flagsService.isEnabled(KnownExperimentId.TOKEN_HIGHLIGHTING)
+    ) {
+      layers.push(new TokenHighlightLayer(this));
+    }
     layers.push(this.syntaxLayer);
     // Get layers from plugins (if any).
     layers.push(...this.jsAPI.getDiffLayers(path));
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host_test.js b/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host_test.js
index b24b3ba..344f9d8 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host_test.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host_test.js
@@ -1270,7 +1270,7 @@
     test('gr-diff-host provides syntax highlighting layer', async () => {
       stubRestApi('getDiff').returns(Promise.resolve({content: []}));
       await element.reload();
-      assert.equal(element.$.diff.layers[1], element.syntaxLayer);
+      assert.equal(element.$.diff.layers[0], element.syntaxLayer);
     });
 
     test('rendering normal-sized diff does not disable syntax', () => {
@@ -1324,7 +1324,7 @@
     test('gr-diff-host provides syntax highlighting layer', async () => {
       stubRestApi('getDiff').returns(Promise.resolve({content: []}));
       await element.reload();
-      assert.equal(element.$.diff.layers[1], element.syntaxLayer);
+      assert.equal(element.$.diff.layers[0], element.syntaxLayer);
     });
 
     test('syntax layer should be disabled', () => {
diff --git a/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread.ts b/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread.ts
index 39a87a2..d6aae5c 100644
--- a/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread.ts
+++ b/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread.ts
@@ -54,6 +54,7 @@
 import {CustomKeyboardEvent} from '../../../types/events';
 import {LineNumber, FILE} from '../../diff/gr-diff/gr-diff-line';
 import {GrButton} from '../gr-button/gr-button';
+import {KnownExperimentId} from '../../../services/flags/flags';
 import {DiffInfo, DiffPreferencesInfo} from '../../../types/diff';
 import {RenderPreferences} from '../../../api/diff';
 import {
@@ -211,6 +212,8 @@
 
   private readonly reporting = appContext.reportingService;
 
+  private readonly flagsService = appContext.flagsService;
+
   private readonly commentsService = appContext.commentsService;
 
   readonly storage = appContext.storageService;
@@ -357,7 +360,9 @@
   _getLayers(diff?: DiffInfo) {
     if (!diff) return [];
     const layers = [];
-    layers.push(new TokenHighlightLayer(this));
+    if (this.flagsService.isEnabled(KnownExperimentId.TOKEN_HIGHLIGHTING)) {
+      layers.push(new TokenHighlightLayer(this));
+    }
     layers.push(this.syntaxLayer);
     return layers;
   }
diff --git a/polygerrit-ui/app/services/flags/flags.ts b/polygerrit-ui/app/services/flags/flags.ts
index 21f3aa4..ef5fde2 100644
--- a/polygerrit-ui/app/services/flags/flags.ts
+++ b/polygerrit-ui/app/services/flags/flags.ts
@@ -25,6 +25,7 @@
  */
 export enum KnownExperimentId {
   NEW_IMAGE_DIFF_UI = 'UiFeature__new_image_diff_ui',
+  TOKEN_HIGHLIGHTING = 'UiFeature__token_highlighting',
   CHECKS_DEVELOPER = 'UiFeature__checks_developer',
   NEW_REPLY_DIALOG = 'UiFeature__new_reply_dialog',
   SUBMIT_REQUIREMENTS_UI = 'UiFeature__submit_requirements_ui',