Override SigninManager::SignOut if force-signin is enabled.

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

Index: chrome/browser/resources/settings/people_page/people_page.js
diff --git a/chrome/browser/resources/settings/people_page/people_page.js b/chrome/browser/resources/settings/people_page/people_page.js
index 400bb0f1f90c0a6620709ebaf8a0513da7e44cde..be02e3f9ac8ebaaf799b790bba07c98831beb96a 100644
--- a/chrome/browser/resources/settings/people_page/people_page.js
+++ b/chrome/browser/resources/settings/people_page/people_page.js
@@ -138,6 +138,7 @@ Polymer({
           this.handleEasyUnlockEnabledStatusChanged_.bind(this));
     }
 </if>
+    this.needSignout = false;
   },
 
   /** @protected */
@@ -229,8 +230,15 @@ Polymer({
 
   /** @private */
   onDisconnectClosed_: function() {

[tommycli, 2016/10/25 18:20:21]

This is fired when a Javascript dialog closes, so it can occur before all the
other browser windows close.

I think if you need to defer signout until after all the browser windows close,
that needs to be handled on the C++ side, and can't be done here in JavaScript.

I don't think you can determine if all the browser windows have closed in
JavaScript.

[zmin, 2016/10/25 18:52:12]

Browser window closing is triggered by signout when force signin enabled. 
Moving the signout here to make sure the window will only be closed after
settings.navigateToPreviousRoute() finished. So that when the browser is opened
next time, the session will be restored to chrome://md-settings but not
chrome://me-settings/signOut

[tommycli, 2016/10/25 19:03:30]

I see. If that's all you need, I suggest within the onDisconnectConfirm_ method,
do:

// Navigate to previous route before signout so session restore does
// not restore to the signout dialog. Dialog will be automatically
// closed by the route change.
settings.navigateToPreviousRoute();
this.syncBrowserProxy_.signOut(deleteProfile);


And you can remove the this.$.disconnectDialog.close() call. See if that works.

[zmin, 2016/10/25 21:02:58]

Done.

-    if (settings.getCurrentRoute() == settings.Route.SIGN_OUT)
+    if (settings.getCurrentRoute() == settings.Route.SIGN_OUT) {
       settings.navigateToPreviousRoute();
+      // Do the signout in the end because it will close all windows when force
+      // signin enabled.
+      setTimeout(function() {
+       if (this.needSignout)
+          this.syncBrowserProxy_.signOut(this.deleteProfile);
+      }.bind(this));
+    }
   },
 
   /** @private */
@@ -247,8 +255,8 @@ Polymer({
   onDisconnectConfirm_: function() {
     var deleteProfile = !!this.syncStatus.domain ||
         (this.$.deleteProfile && this.$.deleteProfile.checked);
-    this.syncBrowserProxy_.signOut(deleteProfile);
-
+    this.needSignout = true;
+    this.deleteProfile = deleteProfile;
     this.$.disconnectDialog.close();
   },