Introduce AudioOutputResampler for browser side resampling.

media/base/sinc_resampler.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 // Input buffer layout, dividing the total buffer into regions (r0_ - r5_):
 //
 // |----------------|-----------------------------------------|----------------|
 //
 //                                   kBlockSize + kKernelSize / 2
 //                   <--------------------------------------------------------->
@@ skipping 196 matching lines @@
     // Step (4)
     // Refresh the buffer with more input.
     read_cb_.Run(r5_, kBlockSize);
   }
 }
 
 int SincResampler::ChunkSize() {
   return kBlockSize / io_sample_rate_ratio_;
 }
 
+void SincResampler::Flush() {
+  virtual_source_idx_ = 0;
+  buffer_primed_ = false;
+  memset(input_buffer_.get(), 0, sizeof(*input_buffer_.get()) * kBufferSize);
+}
+
 float SincResampler::Convolve(const float* input_ptr, const float* k1,
                               const float* k2,
                               double kernel_interpolation_factor) {
   // Rely on function level static initialization to keep ConvolveProc selection
   // thread safe.
   typedef float (*ConvolveProc)(const float* src, const float* k1,
                                 const float* k2,
                                 double kernel_interpolation_factor);
 #if defined(ARCH_CPU_X86_FAMILY) && defined(__SSE__)
   static const ConvolveProc kConvolveProc =
@@ skipping 62 matching lines @@
   float result;
   m_sums2 = _mm_add_ps(_mm_movehl_ps(m_sums1, m_sums1), m_sums1);
   _mm_store_ss(&result, _mm_add_ss(m_sums2, _mm_shuffle_ps(
       m_sums2, m_sums2, 1)));
 
   return result;
 }
 #endif
 
 }  // namespace media