Http cache: Don't attempt to doom the same entry multiple times

net/http/http_cache.cc

 // Copyright (c) 2012 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 "net/http/http_cache.h"
 
 #include <algorithm>
 
 #include "base/compiler_specific.h"
 
@@ skipping 842 matching lines @@
   if (entry->writer) {
     DCHECK(trans == entry->writer);
 
     // Assume there was a failure.
     bool success = false;
     if (cancel) {
       DCHECK(entry->disk_entry);
       // This is a successful operation in the sense that we want to keep the
       // entry.
       success = trans->AddTruncatedFlag();
+      // The previous operation may have deleted the entry.
+      if (!trans->entry())
+        return;
     }
     DoneWritingToEntry(entry, success);
   } else {
     DoneReadingFromEntry(entry, trans);
   }
 }
 
 void HttpCache::DoneWritingToEntry(ActiveEntry* entry, bool success) {
   DCHECK(entry->readers.empty());
 
@@ skipping 300 matching lines @@
     building_backend_ = false;
     DeletePendingOp(pending_op);
   }
 
   // The cache may be gone when we return from the callback.
   if (!item->DoCallback(result, backend))
     item->NotifyTransaction(result, NULL);
 }
 
 }  // namespace net