Update common_audio

Corresponds to upstream commit 524e9b043e7e86fd72353b987c9d5f6a1ebf83e1

Update notes:

 * Moved src/ to webrtc/ to easily diff against the third_party/webrtc
   in the chromium tree

 * ARM/NEON/MIPS support is not yet hooked up

 * Tests have not been copied

webrtc/modules/audio_processing/aec/aec.gypi

@@ -0,0 +1,40 @@
+# Copyright (c) 2011 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.
+
+{
+  'targets': [
+    {
+      'target_name': 'aec',
+      'type': '<(library)',
+      'dependencies': [
+        '<(webrtc_root)/common_audio/common_audio.gyp:spl',
+        'apm_util'
+      ],
+      'include_dirs': [
+        'interface',
+      ],
+      'direct_dependent_settings': {
+        'include_dirs': [
+          'interface',
+        ],
+      },
+      'sources': [
+        'interface/echo_cancellation.h',
+        'echo_cancellation.c',
+        'aec_core.h',
+        'aec_core.c',
+        'aec_core_sse2.c',
+        'aec_rdft.h',
+        'aec_rdft.c',
+        'aec_rdft_sse2.c',
+        'resampler.h',
+        'resampler.c',
+      ],
+    },
+  ],
+}