Enable chrome.mdns for Chrome Apps

chrome/browser/extensions/api/mdns/mdns_api.cc

Index: chrome/browser/extensions/api/mdns/mdns_api.cc
diff --git a/chrome/browser/extensions/api/mdns/mdns_api.cc b/chrome/browser/extensions/api/mdns/mdns_api.cc
index 572ae1eec7b08e50906f96f94aeda0314b75d1c0..d27c448bca168a0a37a171f91f9abcf5deb2fde0 100644
--- a/chrome/browser/extensions/api/mdns/mdns_api.cc
+++ b/chrome/browser/extensions/api/mdns/mdns_api.cc
@@ -10,6 +10,7 @@
 #include "base/profiler/scoped_profile.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/common/extensions/api/mdns.h"
+#include "extensions/browser/extension_registry.h"
 
 namespace extensions {
 
@@ -22,7 +23,11 @@ const char kCastServiceType[] = "_googlecast._tcp.local";
 const char kPrivetServiceType[] = "_privet._tcp.local";
 const char kTestServiceType[] = "_testing._tcp.local";
 
-bool IsServiceTypeWhitelisted(const std::string& service_type) {
+bool IsServiceTypeWhitelisted(const std::string& service_type,
+                              bool is_extension) {
+  if (!is_extension) {
+    return true;
+  }
   return service_type == kCastServiceType ||
          service_type == kPrivetServiceType ||
          service_type == kTestServiceType;
@@ -109,21 +114,33 @@ void MDnsAPI::UpdateMDnsListeners(const EventListenerInfo& details) {
   std::set<std::string> removed_service_types =
       base::STLSetDifference<std::set<std::string> >(
           service_types_, new_service_types);
+  service_types_ = new_service_types;
 
   // Update the registry.
   DnsSdRegistry* registry = dns_sd_registry();
+
+  const extensions::ExtensionRegistry* ext_registry =

[not at google - send to devlin, 2014/11/17 23:22:15]

This file is in the extensions namespace, no extensions:: necessary.

[Red Daly, 2014/11/19 21:31:50]

Done.

+      extensions::ExtensionRegistry::Get(details.browser_context);
+  if (!ext_registry) {

[not at google - send to devlin, 2014/11/17 23:22:15]

There should always be an ExtensionRegistry, since the extension system has
started (given we're receiving extension function calls).

[Red Daly, 2014/11/19 21:31:50]

Done.

+    return;
+  }
+  const extensions::Extension* extension = ext_registry->GetExtensionById(

[not at google - send to devlin, 2014/11/17 23:22:15]

Why do you want all extensions, rather than just the enabled ones?

[Red Daly, 2014/11/19 21:31:50]

I assumed the extension is enabled if UpdateMDnsListeners is called for it, so
ENABLED and EVERYTHING would be equivalent.  I've changed to ENABLED here
instead of EVERYTHING.

[Red Daly, 2015/01/26 21:55:33]

I checked and this assumption was incorrect: This method is called for disabled
extensions, too.

+      details.extension_id,
+      extensions::ExtensionRegistry::EVERYTHING);
+  if (!extension) {
+    return;
+  }
+
   for (std::set<std::string>::iterator it = added_service_types.begin();
        it != added_service_types.end(); ++it) {
-    if (IsServiceTypeWhitelisted(*it))
+    if (IsServiceTypeWhitelisted(*it, extension->is_extension()))

[not at google - send to devlin, 2014/11/17 23:22:15]

I don't understand what the fact that an Extension is has anything to do with
whether some service type is whitelisted?

[Red Daly, 2014/11/19 21:31:50]

This change is in response to Mark's earlier comment.  We would like to preserve
the existing service whitelist for extensions but allow apps to discover all
types of services.

       registry->RegisterDnsSdListener(*it);
   }
   for (std::set<std::string>::iterator it = removed_service_types.begin();
        it != removed_service_types.end(); ++it) {
-    if (IsServiceTypeWhitelisted(*it))
+    if (IsServiceTypeWhitelisted(*it, extension->is_extension()))
       registry->UnregisterDnsSdListener(*it);
   }
-
-  service_types_ = new_service_types;
 }
 
 void MDnsAPI::OnDnsSdEvent(const std::string& service_type,