Add checkbox to allow auto signing in with a saved password.

Screenshot attached to bug.

BUG=620002
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2237533002
Cr-Commit-Position: refs/heads/master@{#412614}

chrome/app/settings_strings.grdp

@@ -317,6 +317,12 @@
   <message name="IDS_SETTINGS_PASSWORDS" desc="Name for the password section and toggle">
     Manage passwords
   </message>
+  <message name="IDS_SETTINGS_PASSWORDS_AUTOSIGNIN_CHECKBOX_LABEL" desc="Label for a checkbox that allows users to sign in automatically to websites when their credentials are already saved.">
+    Auto Sign-in
+  </message>
+  <message name="IDS_SETTINGS_PASSWORDS_AUTOSIGNIN_CHECKBOX_DESC" desc="Text that describes the 'Auto Sign-in' functionality to users.">
+    Automatically sign in to websites using stored credentials. When the feature is disabled, you will be asked for confirmation every time before signing in to a website.
+  </message>
   <message name="IDS_SETTINGS_PASSWORDS_DETAIL" desc="Description of what toggling the 'Manage passwords' setting does. Immediately underneath IDS_SETTINGS_PASSWORDS">
     Offer to save your web passwords
   </message>

chrome/browser/extensions/api/settings_private/prefs_util.cc

@@ -115,6 +115,8 @@ const PrefsUtil::TypedPrefMap& PrefsUtil::GetWhitelistedKeys() {
       settings_private::PrefType::PREF_TYPE_NUMBER;
   (*s_whitelist)["profile.password_manager_enabled"] =
       settings_private::PrefType::PREF_TYPE_BOOLEAN;
+  (*s_whitelist)["credentials_enable_autosignin"] =
+      settings_private::PrefType::PREF_TYPE_BOOLEAN;
   (*s_whitelist)["safebrowsing.enabled"] =
       settings_private::PrefType::PREF_TYPE_BOOLEAN;
   (*s_whitelist)["safebrowsing.extended_reporting_enabled"] =

chrome/browser/resources/settings/passwords_and_forms_page/passwords_and_forms_page.html

@@ -57,7 +57,7 @@
             search-term="{{passwordFilter_}}">
           <passwords-section saved-passwords="[[savedPasswords]]"
               id="passwordSection" password-exceptions="[[passwordExceptions]]"
-              filter="[[passwordFilter_]]">
+              filter="[[passwordFilter_]]" prefs="{{prefs}}">
           </passwords-section>
         </settings-subpage>
       </template>

chrome/browser/resources/settings/passwords_and_forms_page/passwords_section.html

@@ -6,6 +6,7 @@
 <link rel="import" href="chrome://resources/cr_elements/cr_shared_menu/cr_shared_menu.html">
 <link rel="import" href="/passwords_and_forms_page/password_edit_dialog.html">
 <link rel="import" href="/passwords_and_forms_page/passwords_shared_css.html">
+<link rel="import" href="/prefs/prefs.html">
 <link rel="import" href="/settings_shared_css.html">
 
 <dom-module id="passwords-section">
@@ -25,6 +26,10 @@
         width: 0;
       }
 
+      #autosigninCheckbox {
+        margin-bottom: 24px;
+      }
+
       .website-column {
         flex: 3;
       }
@@ -49,6 +54,11 @@
         @apply(--settings-actionable);
       }
     </style>
+    <settings-checkbox id="autosigninCheckbox"
+        pref="{{prefs.credentials_enable_autosignin}}"
+        label="$i18n{passwordsAutosigninLabel}"
+        sub-label="$i18n{passwordsAutosigninDescription}">
+    </settings-checkbox>
     <div id="manageLink">$i18nRaw{managePasswordsLabel}</div>
     <div class="heading">$i18n{savedPasswordsHeading}</div>
     <div class="item-list">

chrome/browser/resources/settings/passwords_and_forms_page/passwords_section.js

@@ -21,6 +21,12 @@ Polymer({
   is: 'passwords-section',
 
   properties: {
+    /** Preferences state. */
+    prefs: {
+      type: Object,
+      notify: true,
+    },
+
     /**
      * An array of passwords to display.
      * @type {!Array<!chrome.passwordsPrivate.PasswordUiEntry>}

chrome/browser/ui/webui/settings/md_settings_localized_strings_provider.cc

@@ -806,6 +806,10 @@ void AddPasswordsAndFormsStrings(content::WebUIDataSource* html_source) {
       {"addCreditCardTitle", IDS_SETTINGS_ADD_CREDIT_CARD_TITLE},
       {"autofillDetail", IDS_SETTINGS_AUTOFILL_DETAIL},
       {"passwords", IDS_SETTINGS_PASSWORDS},
+      {"passwordsAutosigninLabel",
+       IDS_SETTINGS_PASSWORDS_AUTOSIGNIN_CHECKBOX_LABEL},
+      {"passwordsAutosigninDescription",
+       IDS_SETTINGS_PASSWORDS_AUTOSIGNIN_CHECKBOX_DESC},
       {"passwordsDetail", IDS_SETTINGS_PASSWORDS_DETAIL},
       {"savedPasswordsHeading", IDS_SETTINGS_PASSWORDS_SAVED_HEADING},
       {"passwordExceptionsHeading", IDS_SETTINGS_PASSWORDS_EXCEPTIONS_HEADING},