Fix clang style warnings in webrtc/modules/audio_coding/neteq

Mostly this consists of marking functions with override when
applicable, and moving function bodies from .h to .cc files.

BUG=163
R=henrik.lundin@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/44109004

Cr-Commit-Position: refs/heads/master@{#8960}
diff --git a/webrtc/modules/audio_coding/neteq/expand.cc b/webrtc/modules/audio_coding/neteq/expand.cc
index d13c2cd..15d7a84 100644
--- a/webrtc/modules/audio_coding/neteq/expand.cc
+++ b/webrtc/modules/audio_coding/neteq/expand.cc
@@ -24,6 +24,32 @@
 
 namespace webrtc {
 
+Expand::Expand(BackgroundNoise* background_noise,
+               SyncBuffer* sync_buffer,
+               RandomVector* random_vector,
+               int fs,
+               size_t num_channels)
+    : random_vector_(random_vector),
+      sync_buffer_(sync_buffer),
+      first_expand_(true),
+      fs_hz_(fs),
+      num_channels_(num_channels),
+      consecutive_expands_(0),
+      background_noise_(background_noise),
+      overlap_length_(5 * fs / 8000),
+      lag_index_direction_(0),
+      current_lag_index_(0),
+      stop_muting_(false),
+      channel_parameters_(new ChannelParameters[num_channels_]) {
+  assert(fs == 8000 || fs == 16000 || fs == 32000 || fs == 48000);
+  assert(fs <= kMaxSampleRate);  // Should not be possible.
+  assert(num_channels_ > 0);
+  memset(expand_lags_, 0, sizeof(expand_lags_));
+  Reset();
+}
+
+Expand::~Expand() = default;
+
 void Expand::Reset() {
   first_expand_ = true;
   consecutive_expands_ = 0;
@@ -289,6 +315,10 @@
   stop_muting_ = true;
 }
 
+size_t Expand::overlap_length() const {
+  return overlap_length_;
+}
+
 void Expand::InitializeForAnExpandPeriod() {
   lag_index_direction_ = 1;
   current_lag_index_ = -1;
@@ -712,6 +742,18 @@
   }
 }
 
+Expand::ChannelParameters::ChannelParameters()
+    : mute_factor(16384),
+      ar_gain(0),
+      ar_gain_scale(0),
+      voice_mix_factor(0),
+      current_voice_mix_factor(0),
+      onset(false),
+      mute_slope(0) {
+  memset(ar_filter, 0, sizeof(ar_filter));
+  memset(ar_filter_state, 0, sizeof(ar_filter_state));
+}
+
 int16_t Expand::Correlation(const int16_t* input, size_t input_length,
                             int16_t* output, int16_t* output_scale) const {
   // Set parameters depending on sample rate.