Adding PortAllocator option to support cases where sockets can't be bound.

webrtc/p2p/base/portallocator.h

Index: webrtc/p2p/base/portallocator.h
diff --git a/webrtc/p2p/base/portallocator.h b/webrtc/p2p/base/portallocator.h
index a77b037e7294133973f83bc41f49ba2dabb836bc..a13182bf4cf8c0cb89f4110b9dd11e24895d073a 100644
--- a/webrtc/p2p/base/portallocator.h
+++ b/webrtc/p2p/base/portallocator.h
@@ -77,6 +77,15 @@ enum {
 
   // When specified, do not collect IPv6 ICE candidates on Wi-Fi.
   PORTALLOCATOR_ENABLE_IPV6_ON_WIFI = 0x4000,
+
+  // When this flag is set, ports not bound to any specific network interface
+  // will be used, in addition to normal ports bound to the enumerated
+  // interfaces. Without this flag, these "any address" ports would only be
+  // used when network enumeration fails or is disabled. But under certain
+  // conditions, these ports may succeed where others fail, so they may allow
+  // the application to work in a wider variety of environments, at the expense
+  // of having to allocate additional candidates.
+  PORTALLOCATOR_ENABLE_ANY_ADDRESS_PORTS = 0x8000,
 };
 
 // Defines various reasons that have caused ICE regathering.