Do FilteringNetworkManager::CheckPermission from new Initialize method.

content/renderer/p2p/port_allocator.cc

Index: content/renderer/p2p/port_allocator.cc
diff --git a/content/renderer/p2p/port_allocator.cc b/content/renderer/p2p/port_allocator.cc
index f2a9f1d912c19d1b91ef6a4f0515fd0c1485839e..00ee3beddabaedf7ea165e92f11bac14274f90c3 100644
--- a/content/renderer/p2p/port_allocator.cc
+++ b/content/renderer/p2p/port_allocator.cc
@@ -27,6 +27,9 @@ P2PPortAllocator::P2PPortAllocator(
       socket_dispatcher_(socket_dispatcher),
       config_(config),
       origin_(origin) {
+  DCHECK(socket_dispatcher);
+  DCHECK(network_manager_);
+  DCHECK(socket_factory);
   uint32_t flags = 0;
   if (!config_.enable_multiple_routes) {
     flags |= cricket::PORTALLOCATOR_DISABLE_ADAPTER_ENUMERATION;
@@ -51,4 +54,9 @@ P2PPortAllocator::P2PPortAllocator(
 
 P2PPortAllocator::~P2PPortAllocator() {}
 
+void P2PPortAllocator::Initialize() {
+  BasicPortAllocator::Initialize();
+  network_manager_->Initialize();
+}
+
 }  // namespace content