Introduce lock screen app context to extension features

chrome/browser/extensions/chrome_extensions_browser_client.cc

 // Copyright 2013 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.
 
 #include "chrome/browser/extensions/chrome_extensions_browser_client.h"
 
 #include <utility>
 
 #include "base/command_line.h"
 #include "base/memory/ptr_util.h"
@@ skipping 421 matching lines @@
     return nullptr;
   return navigation_data->GetExtensionNavigationUIData();
 }
 
 KioskDelegate* ChromeExtensionsBrowserClient::GetKioskDelegate() {
   if (!kiosk_delegate_)
     kiosk_delegate_.reset(new ChromeKioskDelegate());
   return kiosk_delegate_.get();
 }
 
+bool ChromeExtensionsBrowserClient::IsLockScreenContext(

[Devlin, 2017/06/01 22:17:58]

Is there a race condition here?  The comment in extension service implies that
we don't know if a profile is a lock screen profile at initialization; are we
sure that this will only be called after the appropriate values are set?

[tbarzic, 2017/06/02 00:49:05]

I think it should be fine - renderers for apps launched in sign-in profile after
the sign-in profile becomes "lock-screen" profile (i.e. the ones that should
have lock screen context) should be created after session starts (there might be
some apps installed in the profile from before, but it is not expected for them
to run after user session is created). Though, checking session state would
probably be more in line with what's done in extension_service.

I'm not too happy with the fact that sign-in profile essentially goes from being
'login context' to being 'lock screen' context (seems a little too fragile for
my taste), so I intend to look into introducing new profile type designated for
lock screen apps before the feature launches (but don't want to block other
pieces of the feature on it).

[Devlin, 2017/06/03 02:19:14]

+1 to having this be a new state in the future.

+    content::BrowserContext* context) {
+#if defined(OS_CHROMEOS)
+  return chromeos::ProfileHelper::IsSigninProfile(
+             Profile::FromBrowserContext(context)) &&
+         user_manager::UserManager::Get()->IsUserLoggedIn();
+#else
+  return false;
+#endif
+}
 }  // namespace extensions