Make extensions developer mode adhere to policy

chrome/browser/resources/extensions/extensions.js

Index: chrome/browser/resources/extensions/extensions.js
diff --git a/chrome/browser/resources/extensions/extensions.js b/chrome/browser/resources/extensions/extensions.js
index fbf7b3cb2a4dcc18f7b7bbd05364d9aa12e2ac26..9f349af8f3b84496828bfd10830a214516454e64 100644
--- a/chrome/browser/resources/extensions/extensions.js
+++ b/chrome/browser/resources/extensions/extensions.js
@@ -196,6 +196,8 @@ cr.define('extensions', function() {
 
       /** @const */
       var supervised = profileInfo.isSupervised;
+      var developerModeControlledByPolicy =
+          profileInfo.isDeveloperModeControlledByPolicy;
 
       var pageDiv = $('extension-settings');
       pageDiv.classList.toggle('profile-is-supervised', supervised);
@@ -203,7 +205,13 @@ cr.define('extensions', function() {
 
       var devControlsCheckbox = $('toggle-dev-on');
       devControlsCheckbox.checked = profileInfo.inDeveloperMode;
-      devControlsCheckbox.disabled = supervised;
+      devControlsCheckbox.disabled =
+          supervised || developerModeControlledByPolicy;
+
+      // This is necessary e.g. if developer mode is now disabled by policy
+      // but extension developer tools were visible.
+      this.updateDevControlsVisibility_(false);
+      this.setDevToggleControlledIndicator_(developerModeControlledByPolicy);
 
       $('load-unpacked').disabled = !profileInfo.canLoadUnpacked;
       var extensionList = $('extension-settings-list');
@@ -219,6 +227,32 @@ cr.define('extensions', function() {
     },
 
     /**
+     * Shows or hides the 'controlled by policy' indicator on the dev-toggle
+     * checkbox.
+     * @param {boolean} devModeControlledByPolicy true if the indicator
+     *     should be showing.
+     * @private
+     */
+    setDevToggleControlledIndicator_: function(devModeControlledByPolicy) {
+      var devToggleControlledIndicator = document.querySelector(
+          '#dev-toggle .controlled-setting-indicator');
+
+      if (!(devToggleControlledIndicator instanceof cr.ui.ControlledIndicator))
+        cr.ui.ControlledIndicator.decorate(devToggleControlledIndicator);
+
+      if (devModeControlledByPolicy) {
+        var controlledBy = 'policy';
+        devToggleControlledIndicator.setAttribute(
+           'controlled-by', controlledBy);
+        devToggleControlledIndicator.setAttribute(
+            'text' + controlledBy,
+            loadTimeData.getString('extensionControlledSettingPolicy'));
+      } else {
+        devToggleControlledIndicator.removeAttribute('controlled-by');
+      }
+    },
+
+    /**
      * Shows the loading spinner and hides elements that shouldn't be visible
      * while loading.
      * @param {boolean} isLoading