Enable login screen apps.

extensions/browser/process_manager.cc

Index: extensions/browser/process_manager.cc
diff --git a/extensions/browser/process_manager.cc b/extensions/browser/process_manager.cc
index dc3b5e71266cc0a0b0c4ed56d36d244f6ed572b3..75f56052a39d29ac362157e49f239fa33de25feb 100644
--- a/extensions/browser/process_manager.cc
+++ b/extensions/browser/process_manager.cc
@@ -365,7 +365,8 @@ bool ProcessManager::CreateBackgroundHost(const Extension* extension,
   // Don't create hosts if the embedder doesn't allow it.
   ProcessManagerDelegate* delegate =
       ExtensionsBrowserClient::Get()->GetProcessManagerDelegate();
-  if (delegate && !delegate->IsBackgroundPageAllowed(browser_context_))
+  if (delegate &&
+      !delegate->IsBackgroundPageAllowed(browser_context_, extension))
     return false;
 
   // Don't create multiple background hosts for an extension.
@@ -387,7 +388,7 @@ void ProcessManager::MaybeCreateStartupBackgroundHosts() {
   // The embedder might disallow background pages entirely.
   ProcessManagerDelegate* delegate =
       ExtensionsBrowserClient::Get()->GetProcessManagerDelegate();
-  if (delegate && !delegate->IsBackgroundPageAllowed(browser_context_))
+  if (delegate && !delegate->IsBackgroundPageAllowed(browser_context_, nullptr))

[achuithb, 2017/03/09 14:31:06]

This is where extension can be null.

We considered removing this check altogether, but not sure if that's safe.

     return;
 
   // The embedder might want to defer background page loading. For example,
@@ -703,9 +704,13 @@ void ProcessManager::OnExtensionUnloaded(
 
 void ProcessManager::CreateStartupBackgroundHosts() {
   DCHECK(!startup_background_hosts_created_);
+  ProcessManagerDelegate* delegate =
+      ExtensionsBrowserClient::Get()->GetProcessManagerDelegate();
   for (const scoped_refptr<const Extension>& extension :
            extension_registry_->enabled_extensions()) {
-    CreateBackgroundHostForExtensionLoad(this, extension.get());
+    if (delegate &&
+        delegate->IsBackgroundPageAllowed(browser_context_, extension.get()))

[achuithb, 2017/03/09 14:31:06]

We've added this additional check because extension=null allows all extensions
in the signin profile, and this check only allows the ones specified by policy.

+      CreateBackgroundHostForExtensionLoad(this, extension.get());
     for (auto& observer : observer_list_)
       observer.OnBackgroundHostStartup(extension.get());
   }