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/common_audio/signal_processing/energy.c

@@ -0,0 +1,39 @@
+/*
+ *  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.
+ */
+
+
+/*
+ * This file contains the function WebRtcSpl_Energy().
+ * The description header can be found in signal_processing_library.h
+ *
+ */
+
+#include "webrtc/common_audio/signal_processing/include/signal_processing_library.h"
+
+int32_t WebRtcSpl_Energy(int16_t* vector,
+                         size_t vector_length,
+                         int* scale_factor)
+{
+    int32_t en = 0;
+    size_t i;
+    int scaling =
+        WebRtcSpl_GetScalingSquare(vector, vector_length, vector_length);
+    size_t looptimes = vector_length;
+    int16_t *vectorptr = vector;
+
+    for (i = 0; i < looptimes; i++)
+    {
+      en += (*vectorptr * *vectorptr) >> scaling;
+      vectorptr++;
+    }
+    *scale_factor = scaling;
+
+    return en;
+}