Add enable_hangout_services_extension flag to GN build.

This does not yet control anything, but is now hooked up to the C++ and grit defines as in GYP.

R=bemasc@chromium.org

Review URL: https://codereview.chromium.org/751613006

Cr-Commit-Position: refs/heads/master@{#306270}

3 files changed, 11 insertions, 2 deletions

diff --git a/build/config/BUILD.gn b/build/config/BUILD.gn
index 0015451..247954b 100644
--- a/build/config/BUILD.gn
+++ b/build/config/BUILD.gn
@@ -204,6 +204,9 @@ config("feature_flags") {
   if (proprietary_codecs) {
     defines += [ "USE_PROPRIETARY_CODECS" ]
   }
+  if (enable_hangout_services_extension) {
+    defines += [ "ENABLE_HANGOUT_SERVICES_EXTENSION=1" ]
+  }
 }
 
 # Debug/release ----------------------------------------------------------------
diff --git a/build/config/features.gni b/build/config/features.gni
index ea31e99..2426af0 100644
--- a/build/config/features.gni
+++ b/build/config/features.gni
@@ -159,3 +159,8 @@ use_brlapi = is_chromeos
 # system).
 # TODO(GYP) also require !embedded to enable.
 use_gconf = is_linux && !is_chromeos
+
+# Hangout services is an extension that adds extra features to Hangouts.
+# For official GYP builds, this flag is set, it will likely need to be
+# parameterized in the future for a similar use.
+enable_hangout_services_extension = false
diff --git a/build/secondary/tools/grit/grit_rule.gni b/build/secondary/tools/grit/grit_rule.gni
index 8726927..d49c4ed 100644
--- a/build/secondary/tools/grit/grit_rule.gni
+++ b/build/secondary/tools/grit/grit_rule.gni
@@ -182,8 +182,9 @@ if (enable_google_now) {
 if (enable_webrtc) {
   grit_defines += [ "-D", "enable_webrtc" ]
 }
-# Note: enable_hangout_services_extension is omitted. It is never set in the
-# GYP build. Need to figure out what it's for.
+if (enable_hangout_services_extension) {
+  grit_defines += [ "-D", "enable_hangout_services_extension" ]
+}
 if (enable_task_manager) {
   grit_defines += [ "-D", "enable_task_manager" ]
 }