Settings People Revamp: Cache the selected Sync individual data types.

chrome/browser/resources/settings/people_page/sync_page.js

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 (function() {
 
 /**
  * Names of the radio buttons which allow the user to choose his encryption
  * mechanism.
  * @enum {string}
  */
 var RadioButtonNames = {
   ENCRYPT_WITH_GOOGLE: 'encrypt-with-google',
   ENCRYPT_WITH_PASSPHRASE: 'encrypt-with-passphrase',
 };
 
 /**
+ * Names of the individual data type properties to be cached from
+ * settings.SyncPrefs when the user checks 'Sync All'.
+ * @type {!Array<string>}
+ */
+var SyncPrefsIndividualDataTypes = [
+  'appsSynced',
+  'extensionsSynced',
+  'preferencesSynced',
+  'autofillSynced',
+  'typedUrlsSynced',
+  'themesSynced',
+  'bookmarksSynced',
+  'passwordsSynced',
+  'tabsSynced',
+  'paymentsIntegrationEnabled',
+];
+
+/**
  * @fileoverview
  * 'settings-sync-page' is the settings page containing sync settings.
  *
  * Example:
  *
  *    <iron-animated-pages>
  *      <settings-sync-page></settings-sync-page>
  *      ... other pages ...
  *    </iron-animated-pages>
  */
@@ skipping 32 matching lines @@
 
     /**
      * The current sync preferences, supplied by SyncBrowserProxy.
      * @type {?settings.SyncPrefs}
      */
     syncPrefs: {
       type: Object,
     },
 
     /**
+     * Caches the individually selected synced data types. This is used to
+     * be able to restore the selections after checking and unchecking Sync All.
+     * @private
+     */
+    cachedSyncPrefs_: {
+      type: Object,
+    },
+
+    /**
      * Whether the "create passphrase" inputs should be shown. These inputs
      * give the user the opportunity to use a custom passphrase instead of
      * authenticating with his Google credentials.
      * @private
      */
     creatingNewPassphrase_: {
       type: Boolean,
       value: false,
     },
 
@@ skipping 97 matching lines @@
     if (!this.syncPrefs.autofillRegistered || !this.syncPrefs.autofillSynced)
       this.set('syncPrefs.paymentsIntegrationEnabled', false);
 
     // Hide the new passphrase box if the sync data has been encrypted.
     if (this.syncPrefs.encryptAllData)
       this.creatingNewPassphrase_ = false;
   },
 
   /**
    * Handler for when the sync all data types checkbox is changed.
-   * @param {Event} event
+   * @param {!Event} event
    * @private
    */
   onSyncAllDataTypesChanged_: function(event) {
     if (event.target.checked) {
       this.set('syncPrefs.syncAllDataTypes', true);
-      this.set('syncPrefs.appsSynced', true);
-      this.set('syncPrefs.extensionsSynced', true);
-      this.set('syncPrefs.preferencesSynced', true);
-      this.set('syncPrefs.autofillSynced', true);
-      this.set('syncPrefs.typedUrlsSynced', true);
-      this.set('syncPrefs.themesSynced', true);
-      this.set('syncPrefs.bookmarksSynced', true);
-      this.set('syncPrefs.passwordsSynced', true);
-      this.set('syncPrefs.tabsSynced', true);
-      this.set('syncPrefs.paymentsIntegrationEnabled', true);
+
+      // Cache the previously selected preference before checking every box.
+      this.cachedSyncPrefs_ = {};
+      for (var dataType of SyncPrefsIndividualDataTypes) {
+        // These are all booleans, so this shallow copy is sufficient.
+        this.cachedSyncPrefs_[dataType] = this.syncPrefs[dataType];
+
+        this.set(['syncPrefs', dataType], true);
+      }
+    } else if (this.cachedSyncPrefs_) {
+      // Restore the previously selected preference.
+      for (dataType of SyncPrefsIndividualDataTypes) {
+        this.set(['syncPrefs', dataType], this.cachedSyncPrefs_[dataType]);
+      }
     }
 
     this.onSingleSyncDataTypeChanged_();
   },
 
   /**
    * Handler for when any sync data type checkbox is changed (except autofill).
    * @private
    */
   onSingleSyncDataTypeChanged_: function() {
@@ skipping 152 matching lines @@
 
     passphraseInput.invalid = emptyPassphrase;
     passphraseConfirmationInput.invalid =
         !emptyPassphrase && mismatchedPassphrase;
 
     return !emptyPassphrase && !mismatchedPassphrase;
   },
 });
 
 })();