Mojo C++ bindings: fix [D]CHECKs in MultiplexRouter and SyncHandleRegistry.

mojo/public/cpp/bindings/lib/multiplex_router.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "mojo/public/cpp/bindings/lib/multiplex_router.h"
 
 #include <stdint.h>
 
 #include <utility>
 
@@ skipping 317 matching lines @@
 
   sync_message_tasks_.clear();
   tasks_.clear();
 
   for (auto iter = endpoints_.begin(); iter != endpoints_.end();) {
     InterfaceEndpoint* endpoint = iter->second.get();
     // Increment the iterator before calling UpdateEndpointStateMayRemove()
     // because it may remove the corresponding value from the map.
     ++iter;
 
-    DCHECK(endpoint->closed());
-    UpdateEndpointStateMayRemove(endpoint, PEER_ENDPOINT_CLOSED);
+    if (!endpoint->closed()) {
+      // This happens when a NotifyPeerEndpointClosed message been received, but
+      // (1) the interface ID hasn't been used to create local endpoint handle;
+      // and (2) a NotifyEndpointClosedBeforeSent hasn't been received.
+      DCHECK(!endpoint->client());
+      DCHECK(endpoint->peer_closed());
+      UpdateEndpointStateMayRemove(endpoint, ENDPOINT_CLOSED);
+    } else {
+      UpdateEndpointStateMayRemove(endpoint, PEER_ENDPOINT_CLOSED);
+    }
   }
 
   DCHECK(endpoints_.empty());
 }
 
 void MultiplexRouter::SetMasterInterfaceName(const std::string& name) {
   DCHECK(thread_checker_.CalledOnValidThread());
   header_validator_->SetDescription(name + " [master] MessageHeaderValidator");
   control_message_handler_.SetDescription(
       name + " [master] PipeControlMessageHandler");
@@ skipping 554 matching lines @@
 
 void MultiplexRouter::AssertLockAcquired() {
 #if DCHECK_IS_ON()
   if (lock_)
     lock_->AssertAcquired();
 #endif
 }
 
 }  // namespace internal
 }  // namespace mojo