Move channel_buffer.{h,cc} to common_audio.

In https://code.google.com/p/webrtc/source/detail?r=8166
I added a check preventing GYP files from referencing
sources above their directory level.
This CL fixes the disallowed reference added in
https://code.google.com/p/webrtc/source/detail?r=8157
by moving channel_buffer.{h,cc} to common_audio for real.

BUG=4185
R=andrew@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/35939004

Cr-Commit-Position: refs/heads/master@{#8190}
git-svn-id: http://webrtc.googlecode.com/svn/trunk@8190 4adac7df-926f-26a2-2b94-8c16560cd09d

webrtc/common_audio/channel_buffer.cc

@@ -0,0 +1,63 @@
+/*
+ *  Copyright (c) 2014 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.
+ */
+
+#include "webrtc/common_audio/channel_buffer.h"
+
+namespace webrtc {
+
+IFChannelBuffer::IFChannelBuffer(int samples_per_channel, int num_channels)
+    : ivalid_(true),
+      ibuf_(samples_per_channel, num_channels),
+      fvalid_(true),
+      fbuf_(samples_per_channel, num_channels) {}
+
+ChannelBuffer<int16_t>* IFChannelBuffer::ibuf() {
+  RefreshI();
+  fvalid_ = false;
+  return &ibuf_;
+}
+
+ChannelBuffer<float>* IFChannelBuffer::fbuf() {
+  RefreshF();
+  ivalid_ = false;
+  return &fbuf_;
+}
+
+const ChannelBuffer<int16_t>* IFChannelBuffer::ibuf_const() const {
+  RefreshI();
+  return &ibuf_;
+}
+
+const ChannelBuffer<float>* IFChannelBuffer::fbuf_const() const {
+  RefreshF();
+  return &fbuf_;
+}
+
+void IFChannelBuffer::RefreshF() const {
+  if (!fvalid_) {
+    assert(ivalid_);
+    const int16_t* const int_data = ibuf_.data();
+    float* const float_data = fbuf_.data();
+    const int length = fbuf_.length();
+    for (int i = 0; i < length; ++i)
+      float_data[i] = int_data[i];
+    fvalid_ = true;
+  }
+}
+
+void IFChannelBuffer::RefreshI() const {
+  if (!ivalid_) {
+    assert(fvalid_);
+    FloatS16ToS16(fbuf_.data(), ibuf_.length(), ibuf_.data());
+    ivalid_ = true;
+  }
+}
+
+}  // namespace webrtc