Fuchsia: Remove overly-restrictive assert from eventhandler

runtime/bin/eventhandler_fuchsia.cc

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #if !defined(DART_IO_DISABLED)
 
 #include "platform/globals.h"
 #if defined(TARGET_OS_FUCHSIA)
 
 #include "bin/eventhandler.h"
@@ skipping 309 matching lines @@
             delete di;
           }
         } else {
           ASSERT(new_mask == 0);
           socket_map_.Remove(GetHashmapKeyFromFd(fd), GetHashmapHashFromFd(fd));
           di->Close();
           LOG_INFO("Closed %d\n", di->fd());
           delete di;
         }
 
-        DartUtils::PostInt32(port, 1 << kDestroyedEvent);
+        bool success = DartUtils::PostInt32(port, 1 << kDestroyedEvent);
+        if (!success) {
+          LOG_ERR("Failed to post destroy event to port %ld", port);
+        }
       } else if (IS_COMMAND(msg[i].data, kReturnTokenCommand)) {
         int count = TOKEN_COUNT(msg[i].data);
         intptr_t old_mask = di->Mask();
         LOG_INFO("\t Return Token: %d: %lx\n", di->fd(), old_mask);
         di->ReturnTokens(msg[i].dart_port, count);
         UpdateEpollInstance(old_mask, di);
       } else if (IS_COMMAND(msg[i].data, kSetEventMaskCommand)) {
         // `events` can only have kInEvent/kOutEvent flags set.
         intptr_t events = msg[i].data & EVENT_MASK;
         ASSERT(0 == (events & ~(1 << kInEvent | 1 << kOutEvent)));
@@ skipping 56 matching lines @@
         intptr_t old_mask = di->Mask();
         Dart_Port port = di->NextNotifyDartPort(event_mask);
         ASSERT(port != 0);
         UpdateEpollInstance(old_mask, di);
         LOG_INFO("HandleEvents: Posting %ld to %ld for fd=%ld\n", event_mask,
                  port, di->fd());
         bool success = DartUtils::PostInt32(port, event_mask);
         if (!success) {
           // This can happen if e.g. the isolate that owns the port has died
           // for some reason.
-          FATAL2("Failed to post event for fd %ld to port %ld", di->fd(), port);
+          LOG_ERR("Failed to post event for fd %ld to port %ld", di->fd(),
+                  port);
         }
       }
     }
   }
   if (interrupt_seen) {
     // Handle after socket events, so we avoid closing a socket before we handle
     // the current events.
     HandleInterruptFd();
   }
 }
@@ skipping 83 matching lines @@
   // The hashmap does not support keys with value 0.
   return dart::Utils::WordHash(fd + 1);
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_FUCHSIA)
 
 #endif  // !defined(DART_IO_DISABLED)