Fix Simple Cache race on multiple dooms in flight.

net/disk_cache/simple/simple_entry_impl.cc

 // Copyright (c) 2013 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/disk_cache/simple/simple_entry_impl.h"
 
 #include <algorithm>
 #include <cstring>
 #include <vector>
 
@@ skipping 547 matching lines @@
     return;
   backend_->OnDeactivated(this);
 }
 
 void SimpleEntryImpl::MarkAsDoomed() {
   doomed_ = true;
   if (!backend_.get())
     return;
   backend_->index()->Remove(entry_hash_);
   RemoveSelfFromBackend();
+  backend_->OnDoomStart(entry_hash_);

[gavinp, 2013/09/16 12:40:12]

This is a bug. We should only do this on actual doom operations.

 }
 
 void SimpleEntryImpl::RunNextOperationIfNeeded() {
   DCHECK(io_thread_checker_.CalledOnValidThread());
   SIMPLE_CACHE_UMA(CUSTOM_COUNTS,
                    "EntryOperationsPending", cache_type_,
                    pending_operations_.size(), 0, 100, 20);
   if (!pending_operations_.empty() && state_ != STATE_IO_PENDING) {
     scoped_ptr<SimpleEntryOperation> operation(
         new SimpleEntryOperation(pending_operations_.front()));
@@ skipping 332 matching lines @@
   Closure reply = base::Bind(&SimpleEntryImpl::WriteOperationComplete,
                              this,
                              stream_index,
                              callback,
                              base::Passed(&entry_stat),
                              base::Passed(&result));
   worker_pool_->PostTaskAndReply(FROM_HERE, task, reply);
 }
 
 void SimpleEntryImpl::DoomEntryInternal(const CompletionCallback& callback) {
-  if (backend_)
-    backend_->OnDoomStart(entry_hash_);
   PostTaskAndReplyWithResult(
       worker_pool_, FROM_HERE,
       base::Bind(&SimpleSynchronousEntry::DoomEntry, path_, key_, entry_hash_),
       base::Bind(&SimpleEntryImpl::DoomOperationComplete, this, callback,
                  state_));
   state_ = STATE_IO_PENDING;
 }
 
 void SimpleEntryImpl::CreationOperationComplete(
     const CompletionCallback& completion_callback,
@@ skipping 309 matching lines @@
       type = conflicting ? WRITE_FOLLOWS_CONFLICTING_WRITE
                          : WRITE_FOLLOWS_NON_CONFLICTING_WRITE;
     }
   }
   SIMPLE_CACHE_UMA(ENUMERATION,
                    "WriteDependencyType", cache_type_,
                    type, WRITE_DEPENDENCY_TYPE_MAX);
 }
 
 }  // namespace disk_cache