Moving src/webrtc into src/.

In order to eliminate the WebRTC Subtree mirror in Chromium, 
WebRTC is moving the content of the src/webrtc directory up
to the src/ directory.

NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
TBR=tommi@webrtc.org

Bug: chromium:611808
Change-Id: Iac59c5b51b950f174119565bac87955a7994bc38
Reviewed-on: https://webrtc-review.googlesource.com/1560
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Henrik Kjellander <kjellander@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#19845}

modules/audio_coding/neteq/preemptive_expand.h

@@ -0,0 +1,88 @@
+/*
+ *  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.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ_PREEMPTIVE_EXPAND_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ_PREEMPTIVE_EXPAND_H_
+
+#include <assert.h>
+
+#include "webrtc/modules/audio_coding/neteq/audio_multi_vector.h"
+#include "webrtc/modules/audio_coding/neteq/time_stretch.h"
+#include "webrtc/rtc_base/constructormagic.h"
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+
+// Forward declarations.
+class BackgroundNoise;
+
+// This class implements the PreemptiveExpand operation. Most of the work is
+// done in the base class TimeStretch, which is shared with the Accelerate
+// operation. In the PreemptiveExpand class, the operations that are specific to
+// PreemptiveExpand are implemented.
+class PreemptiveExpand : public TimeStretch {
+ public:
+  PreemptiveExpand(int sample_rate_hz,
+                   size_t num_channels,
+                   const BackgroundNoise& background_noise,
+                   size_t overlap_samples)
+      : TimeStretch(sample_rate_hz, num_channels, background_noise),
+        old_data_length_per_channel_(0),
+        overlap_samples_(overlap_samples) {
+  }
+
+  // This method performs the actual PreemptiveExpand operation. The samples are
+  // read from |input|, of length |input_length| elements, and are written to
+  // |output|. The number of samples added through time-stretching is
+  // is provided in the output |length_change_samples|. The method returns
+  // the outcome of the operation as an enumerator value.
+  ReturnCodes Process(const int16_t *pw16_decoded,
+                      size_t len,
+                      size_t old_data_len,
+                      AudioMultiVector* output,
+                      size_t* length_change_samples);
+
+ protected:
+  // Sets the parameters |best_correlation| and |peak_index| to suitable
+  // values when the signal contains no active speech.
+  void SetParametersForPassiveSpeech(size_t input_length,
+                                     int16_t* best_correlation,
+                                     size_t* peak_index) const override;
+
+  // Checks the criteria for performing the time-stretching operation and,
+  // if possible, performs the time-stretching.
+  ReturnCodes CheckCriteriaAndStretch(const int16_t* input,
+                                      size_t input_length,
+                                      size_t peak_index,
+                                      int16_t best_correlation,
+                                      bool active_speech,
+                                      bool /*fast_mode*/,
+                                      AudioMultiVector* output) const override;
+
+ private:
+  size_t old_data_length_per_channel_;
+  size_t overlap_samples_;
+
+  RTC_DISALLOW_COPY_AND_ASSIGN(PreemptiveExpand);
+};
+
+struct PreemptiveExpandFactory {
+  PreemptiveExpandFactory() {}
+  virtual ~PreemptiveExpandFactory() {}
+
+  virtual PreemptiveExpand* Create(
+      int sample_rate_hz,
+      size_t num_channels,
+      const BackgroundNoise& background_noise,
+      size_t overlap_samples) const;
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ_PREEMPTIVE_EXPAND_H_