To reduce cross-account sync confusion, give the user a warning at sync sign in time if the account they are signing into is different from the account that the profile was previously signed into

TBR=jhawkins@chromium.org
BUG=157761
TEST=Create a new profile and connect it to an account. Make sure it connects
with no warnings. Disconnect the account and try to connect a different
account. Should get a warning as specified in bug description. Pressing
"sign in" again without changing anything should allow the sign in to
processed as expected.

original codereview by rogerta@: http://codereview.chromium.org/11272023/

Review URL: https://codereview.chromium.org/11311016

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@164440 0039d316-1c4b-4281-b951-d872f2087c98

5 files changed, 37 insertions, 0 deletions

diff --git a/chrome/app/chromium_strings.grd b/chrome/app/chromium_strings.grd
index f31cd9a..f35db25b 100644
--- a/chrome/app/chromium_strings.grd
+++ b/chrome/app/chromium_strings.grd
@@ -804,6 +804,9 @@ For Chromium, processes used to display diagnostics information (such as this "a
       <message name="IDS_SYNC_PROMO_V_LEARN_MORE" desc="Learn more link at the bottom of the sync promo.">
         See <ph name="BEGIN_LINK">&lt;a target="_blank" href="$1"&gt;</ph>more benefits<ph name="END_LINK">&lt;/a&gt;</ph> of signing in to Chromium.
       </message>
+      <message name="IDS_SYNC_DIFFERENT_EMAIL" desc="Error message to display when setting up sync for a second time and the user name is different from the previous user name.">
+        You were previously signed in with a different account, signing in will merge your data. Consider creating a new Chromium user via the <ph name="BEGIN_LINK">&lt;a href="chrome://settings/search#Users"&gt;</ph>settings page<ph name="END_LINK">&lt;/a&gt;</ph> for your Chromium stuff.
+      </message>
 
       <!-- One click sign in infobar -->
       <if expr="not pp_ifdef('chromeos')">
diff --git a/chrome/app/google_chrome_strings.grd b/chrome/app/google_chrome_strings.grd
index 3a9a767..800cc82 100644
--- a/chrome/app/google_chrome_strings.grd
+++ b/chrome/app/google_chrome_strings.grd
@@ -728,6 +728,9 @@ For Google Chrome, processes used to display diagnostics information (such as th
       <message name="IDS_SYNC_PROMO_V_LEARN_MORE" desc="Learn more link at the bottom of the sync promo.">
         See <ph name="BEGIN_LINK">&lt;a target="_blank" href="$1"&gt;</ph>more benefits<ph name="END_LINK">&lt;/a&gt;</ph> of signing in to Chrome.
       </message>
+      <message name="IDS_SYNC_DIFFERENT_EMAIL" desc="Error message to display when setting up sync for a second time and the user name is different from the previous user name.">
+        You were previously signed in with a different account, signing in will merge your data. Consider creating a new Chrome user via the <ph name="BEGIN_LINK">&lt;a href="chrome://settings/search#Users"&gt;</ph>settings page<ph name="END_LINK">&lt;/a&gt;</ph> for your Chrome stuff.
+      </message>
 
       <!-- One click sign in infobar -->
       <if expr="not pp_ifdef('chromeos')">
diff --git a/chrome/browser/resources/sync_setup_overlay.html b/chrome/browser/resources/sync_setup_overlay.html
index 86bfecc..0003d7f 100644
--- a/chrome/browser/resources/sync_setup_overlay.html
+++ b/chrome/browser/resources/sync_setup_overlay.html
@@ -76,6 +76,10 @@
                 <a i18n-values="href:invalidPasswordHelpURL" class="help-link"
                     target="_blank">?</a>
               </div>
+              <div id="errormsg-different-email" class="errormsg reset-hidden"
+                  hidden>
+                <span id="different-email"></span>
+              </div>
               <div id="errormsg-fatal" class="errormsg reset-hidden" hidden>
                 <span i18n-content="unrecoverableError"></span>
                 <a i18n-values="href:unrecoverableErrorHelpURL"
diff --git a/chrome/browser/resources/sync_setup_overlay.js b/chrome/browser/resources/sync_setup_overlay.js
index a17b52d..cd7f127 100644
--- a/chrome/browser/resources/sync_setup_overlay.js
+++ b/chrome/browser/resources/sync_setup_overlay.js
@@ -30,6 +30,11 @@ cr.define('options', function() {
   // each other).
   var keystoreEncryptionEnabled_ = false;
 
+  // The last email address that this profile was connected to.  If the profile
+  // was never connected this is an empty string.  Otherwise it is a normalized
+  // email address.
+  var lastEmailAddress_ = '';
+
   /**
    * SyncSetupOverlay class
    * Encapsulated handling of the 'Sync Setup' overlay page.
@@ -82,6 +87,7 @@ cr.define('options', function() {
         chrome.send('SyncSetupStopSyncing');
         self.closeOverlay_();
       };
+      $('different-email').innerHTML = loadTimeData.getString('differentEmail');
     },
 
     showOverlay_: function() {
@@ -751,6 +757,7 @@ cr.define('options', function() {
       $('sync-setup-login').hidden = false;
       this.allowEmptyPassword_ = false;
       this.captchaChallengeActive_ = false;
+      this.lastEmailAddress_ = args.lastEmailAddress;
 
       var f = $('gaia-login-form');
       var email = $('gaia-email');
@@ -816,6 +823,7 @@ cr.define('options', function() {
       $('errormsg-0-email').hidden = true;
       $('errormsg-0-password').hidden = true;
       $('errormsg-1-password').hidden = true;
+      $('errormsg-different-email').hidden = true;
       $('errormsg-0-connection').hidden = true;
       $('errormsg-0-access-code').hidden = true;
       $('errormsg-0-otp').hidden = true;
@@ -848,6 +856,8 @@ cr.define('options', function() {
     },
 
     setErrorVisibility_: function() {
+      var errormsgDifferentEmail = $('errormsg-different-email');
+      var isErrormsgDifferentEmailHidden = errormsgDifferentEmail.hidden;
       this.resetErrorVisibility_();
       var f = $('gaia-login-form');
       var email = $('gaia-email');
@@ -857,6 +867,14 @@ cr.define('options', function() {
         this.setBlurbError_();
         return false;
       }
+      // If email is different from last email, and we have not already warned
+      // the user, tell them now.  Otherwise proceed as usual.
+      if (this.lastEmailAddress_.length > 0 &&
+          email.value != this.lastEmailAddress_ &&
+          isErrormsgDifferentEmailHidden) {
+        errormsgDifferentEmail.hidden = false;
+        return false;
+      }
       // Don't enforce password being non-blank when checking access code (it
       // will have been cleared when the page was displayed).
       if (!this.allowEmptyPassword_ && !passwd.value) {
diff --git a/chrome/browser/ui/webui/sync_setup_handler.cc b/chrome/browser/ui/webui/sync_setup_handler.cc
index 6215cd8..556d803 100644
--- a/chrome/browser/ui/webui/sync_setup_handler.cc
+++ b/chrome/browser/ui/webui/sync_setup_handler.cc
@@ -21,6 +21,7 @@
 #include "chrome/browser/profiles/profile_info_cache.h"
 #include "chrome/browser/profiles/profile_manager.h"
 #include "chrome/browser/profiles/profile_metrics.h"
+#include "chrome/browser/prefs/pref_service.h"
 #include "chrome/browser/signin/signin_manager.h"
 #include "chrome/browser/signin/signin_manager_factory.h"
 #include "chrome/browser/sync/profile_sync_service.h"
@@ -29,6 +30,7 @@
 #include "chrome/browser/ui/webui/signin/login_ui_service_factory.h"
 #include "chrome/browser/ui/webui/sync_promo/sync_promo_ui.h"
 #include "chrome/common/chrome_switches.h"
+#include "chrome/common/pref_names.h"
 #include "chrome/common/url_constants.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/web_contents.h"
@@ -287,6 +289,7 @@ void SyncSetupHandler::GetStaticLocalizedValues(
     { "emailLabel", IDS_SYNC_LOGIN_EMAIL_NEW_LINE },
     { "passwordLabel", IDS_SYNC_LOGIN_PASSWORD_NEW_LINE },
     { "invalidCredentials", IDS_SYNC_INVALID_USER_CREDENTIALS },
+    { "differentEmail", IDS_SYNC_DIFFERENT_EMAIL },
     { "signin", IDS_SYNC_SIGNIN },
     { "couldNotConnect", IDS_SYNC_LOGIN_COULD_NOT_CONNECT },
     { "unrecoverableError", IDS_SYNC_UNRECOVERABLE_ERROR },
@@ -603,6 +606,12 @@ void SyncSetupHandler::DisplayGaiaLoginWithErrorMessage(
   else if (error == GoogleServiceAuthError::CAPTCHA_REQUIRED)
     args.SetBoolean("hideEmailAndPassword", false);
 
+  // Tell the page the previous email address used for sync.  If the user
+  // enters a different email address, he will be shown a warning.
+  std::string last_email = GetProfile()->GetPrefs()->GetString(
+      prefs::kGoogleServicesLastUsername);
+  args.SetString("lastEmailAddress", last_email);
+
   args.SetBoolean("editableUser", editable_user);
   if (!local_error_message.empty())
     args.SetString("errorMessage", local_error_message);