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))

[Devlin, 2017/03/13 19:39:35]

We check this in three different places now, making it a bit redundant. :)

[achuithb, 2017/03/15 00:40:25]

It does seem that way :/

What would you propose?

     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, 2017/03/15 00:40:25]

We could potentially drop this check since we check again in
CreateStartupBackgroundHosts.

I'm just worried about changing a lot of behavior here since this code is quite
tricky, and does different things in different contexts on different platforms. 

[Devlin, 2017/03/17 16:37:23]

This one is somewhat beneficial, since it helps us early-out if no background
pages are allowed.  But we should change it to
AreBackgroundPagesAllowedForContext() (see also comment in the delegate file).

[achuithb, 2017/03/22 00:15:53]

Done.

     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()))

[Devlin, 2017/03/17 16:37:23]

This one should be able to be avoided - we'll check whether or not its allowed
when we try to create it in CreateBackgroundHost().

[achuithb, 2017/03/22 00:15:53]

Done.

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