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diff --git a/media/cdm/ppapi/cdm_logging.h b/media/cdm/ppapi/cdm_logging.h
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+++ b/media/cdm/ppapi/cdm_logging.h
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+// Copyright 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.
+
+// This file defines useful logging macros/methods for CDM adapter.
+
+#ifndef MEDIA_CDM_PPAPI_CDM_LOGGING_H_
+#define MEDIA_CDM_PPAPI_CDM_LOGGING_H_
+
+#include <iostream>
+#include <sstream>
+#include <string>
+
+namespace media {
+
+namespace {
+
+// The following classes/macros are adapted from base/logging.h.
+
+// This class is used to explicitly ignore values in the conditional
+// logging macros.  This avoids compiler warnings like "value computed
+// is not used" and "statement has no effect".
+class LogMessageVoidify {
+ public:
+  LogMessageVoidify() {}
+  // This has to be an operator with a precedence lower than << but
+  // higher than ?:
+  void operator&(std::ostream&) {}
+};
+
+}  // namespace
+
+// This class serves two purposes:
+// (1) It adds common headers to the log message, e.g. timestamp, process ID.
+// (2) It adds a line break at the end of the log message.
+// This class is copied and modified from base/logging.* but is quite different
+// in terms of how things work. This class is designed to work only with the
+// CDM_DLOG() defined below and should not be used for other purposes.
+class CdmLogMessage {
+ public:
+  CdmLogMessage(const char* file, int line);
+  ~CdmLogMessage();
+
+  std::string message() { return stream_.str(); }
+
+ private:
+  std::ostringstream stream_;
+};
+
+// Helper macro which avoids evaluating the arguments to a stream if
+// the condition doesn't hold.
+#define CDM_LAZY_STREAM(stream, condition) \
+  !(condition) ? (void) 0 : LogMessageVoidify() & (stream)
+
+#define CDM_DLOG() CDM_LAZY_STREAM(std::cout, CDM_DLOG_IS_ON()) \
+  << CdmLogMessage(__FILE__, __LINE__).message()
+
+#if defined(NDEBUG)
+#define CDM_DLOG_IS_ON() false
+#else
+#define CDM_DLOG_IS_ON() true
+#endif
+
+}  // namespace media
+
+#endif  // MEDIA_CDM_PPAPI_CDM_LOGGING_H_