Added namespaces in the newly C++ified AEC code

webrtc/modules/audio_processing/aec/aec_core.h

 /*
  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 /*
  * Specifies the interface for the AEC core.
  */
 
 #ifndef WEBRTC_MODULES_AUDIO_PROCESSING_AEC_AEC_CORE_H_
 #define WEBRTC_MODULES_AUDIO_PROCESSING_AEC_AEC_CORE_H_
 
 #include <stddef.h>
 
 #include "webrtc/typedefs.h"
 
+namespace webrtc {
+
 #define FRAME_LEN 80
 #define PART_LEN 64               // Length of partition
 #define PART_LEN1 (PART_LEN + 1)  // Unique fft coefficients
 #define PART_LEN2 (PART_LEN * 2)  // Length of partition * 2
 #define NUM_HIGH_BANDS_MAX 2      // Max number of high bands
 
 typedef float complex_t[2];
 // For performance reasons, some arrays of complex numbers are replaced by twice
 // as long arrays of float, all the real parts followed by all the imaginary
 // ones (complex_t[SIZE] -> float[2][SIZE]). This allows SIMD optimizations and
@@ skipping 93 matching lines @@
 
 // Returns the current |system_delay|, i.e., the buffered difference between
 // far-end and near-end.
 int WebRtcAec_system_delay(AecCore* self);
 
 // Sets the |system_delay| to |value|.  Note that if the value is changed
 // improperly, there can be a performance regression.  So it should be used with
 // care.
 void WebRtcAec_SetSystemDelay(AecCore* self, int delay);
 
+}  // namespace webrtc
+
 #endif  // WEBRTC_MODULES_AUDIO_PROCESSING_AEC_AEC_CORE_H_