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

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

Index: chrome/browser/resources/settings/people_page/sync_page.js
diff --git a/chrome/browser/resources/settings/people_page/sync_page.js b/chrome/browser/resources/settings/people_page/sync_page.js
index c50b263903c447012519667dfd7d8f6da42fe7ef..dba1b03511b0e994e6b088aebeb49fff2fcde02d 100644
--- a/chrome/browser/resources/settings/people_page/sync_page.js
+++ b/chrome/browser/resources/settings/people_page/sync_page.js
@@ -15,6 +15,23 @@ var RadioButtonNames = {
 };
 
 /**
+ * Names of the individual data type properties to be cached from
+ * settings.SyncPrefs when the user checks 'Sync All'.

[dpapad, 2016/06/29 01:00:35]

@type {!Array<string>}

[tommycli, 2016/06/29 18:00:02]

Done.

+ */
+var SyncPrefsIndividualDataTypes = [
+  'appsSynced',
+  'extensionsSynced',
+  'preferencesSynced',
+  'autofillSynced',
+  'typedUrlsSynced',
+  'themesSynced',
+  'bookmarksSynced',
+  'passwordsSynced',
+  'tabsSynced',
+  'paymentsIntegrationEnabled',
+];
+
+/**
  * @fileoverview
  * 'settings-sync-page' is the settings page containing sync settings.
  *
@@ -67,6 +84,15 @@ Polymer({
     },
 
     /**
+     * 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.
@@ -190,16 +216,20 @@ Polymer({
   onSyncAllDataTypesChanged_: function(event) {
     if (event.target.checked) {

[dpapad, 2016/06/29 01:00:35]

Guessing that this file is not compiled, otherwise event.target would need to be
type casted first.

[tommycli, 2016/06/29 18:00:02]

Hi, it is compiled. I think anything on event.target is exempt, since I can
change that property "checked" to any value and it will still compile.

       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 (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_();