Add some instrumentation to investigate a possible UAF.

net/base/net_log.h

 // 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.
 
 #ifndef NET_BASE_NET_LOG_H_
 #define NET_BASE_NET_LOG_H_
 
 #include <string>
 
+#include "build/build_config.h"
+
+// TODO(eroman): Temporary while investigating crbug.com/467797.
+//               Note base::Debug::StackTrace() is not supported in NACL builds
+//               so conditionally disabled it there.
+#ifndef OS_NACL
+#define TEMP_INSTRUMENTATION_467797
+#endif
+
 #include "base/atomicops.h"
 #include "base/basictypes.h"
 #include "base/callback_forward.h"
 #include "base/compiler_specific.h"
+#ifdef TEMP_INSTRUMENTATION_467797
+#include "base/debug/stack_trace.h"
+#endif
 #include "base/observer_list.h"
 #include "base/strings/string16.h"
 #include "base/synchronization/lock.h"
 #include "base/time/time.h"
 #include "net/base/net_export.h"
 
 namespace base {
 class DictionaryValue;
 class Value;
 }
@@ skipping 301 matching lines @@
   ObserverList<ThreadSafeObserver, true> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(NetLog);
 };
 
 // Helper that binds a Source to a NetLog, and exposes convenience methods to
 // output log messages without needing to pass in the source.
 class NET_EXPORT BoundNetLog {
  public:
   BoundNetLog() : net_log_(NULL) {}
+  ~BoundNetLog();
 
   // Add a log entry to the NetLog for the bound source.
   void AddEntry(NetLog::EventType type, NetLog::EventPhase phase) const;
   void AddEntry(NetLog::EventType type,
                 NetLog::EventPhase phase,
                 const NetLog::ParametersCallback& get_parameters) const;
 
   // Convenience methods that call AddEntry with a fixed "capture phase"
   // (begin, end, or none).
   void BeginEvent(NetLog::EventType type) const;
@@ skipping 36 matching lines @@
   bool IsLogging() const;
 
   // Helper to create a BoundNetLog given a NetLog and a SourceType. Takes care
   // of creating a unique source ID, and handles the case of NULL net_log.
   static BoundNetLog Make(NetLog* net_log, NetLog::SourceType source_type);
 
   const NetLog::Source& source() const { return source_; }
   NetLog* net_log() const { return net_log_; }
 
  private:
+#ifdef TEMP_INSTRUMENTATION_467797
+  // TODO(eroman): Temporary while investigating crbug.com/467797
+  enum Liveness {
+    ALIVE = 0xCA11AB13,
+    DEAD = 0xDEADBEEF,
+  };
+#endif
+
   BoundNetLog(const NetLog::Source& source, NetLog* net_log)
       : source_(source), net_log_(net_log) {
   }
 
+  // TODO(eroman): Temporary while investigating crbug.com/467797
+  void CrashIfInvalid() const;
+
   NetLog::Source source_;
   NetLog* net_log_;
+
+#ifdef TEMP_INSTRUMENTATION_467797
+  // TODO(eroman): Temporary while investigating crbug.com/467797
+  Liveness liveness_ = ALIVE;
+  base::debug::StackTrace stack_trace_;
+#endif
 };
 
 }  // namespace net
 
 #endif  // NET_BASE_NET_LOG_H_