diff --git a/webrtc/base/network.cc b/webrtc/base/network.cc
index 8dda89f42c..ff9c01afdf 100644
--- a/webrtc/base/network.cc
+++ b/webrtc/base/network.cc
@@ -163,6 +163,11 @@ NetworkManager::NetworkManager() {
 NetworkManager::~NetworkManager() {
 }
 
+NetworkManager::EnumerationPermission NetworkManager::enumeration_permission()
+    const {
+  return kEnumerationAllowed;
+}
+
 NetworkManagerBase::NetworkManagerBase()
     : enumeration_permission_(NetworkManager::kEnumerationAllowed),
       max_ipv6_networks_(kMaxIPv6Networks),
diff --git a/webrtc/base/network.h b/webrtc/base/network.h
index 1391572adf..c4cd565ab4 100644
--- a/webrtc/base/network.h
+++ b/webrtc/base/network.h
@@ -90,9 +90,7 @@ class NetworkManager {
   virtual void GetNetworks(NetworkList* networks) const = 0;
 
   // return the current permission state of GetNetworks()
-  virtual EnumerationPermission enumeration_permission() const {
-    return kEnumerationAllowed;
-  }
+  virtual EnumerationPermission enumeration_permission() const;
 
   // "AnyAddressNetwork" is a network which only contains single "any address"
   // IP address.  (i.e. INADDR_ANY for IPv4 or in6addr_any for IPv6). This is