Support for AudioContextOptions latencyHint.

components/test_runner/mock_web_audio_device.cc

 // Copyright 2014 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.
 
 #include "components/test_runner/mock_web_audio_device.h"
 
 namespace test_runner {
 
-MockWebAudioDevice::MockWebAudioDevice(double sample_rate)
-    : sample_rate_(sample_rate) {}
+MockWebAudioDevice::MockWebAudioDevice(double sample_rate,
+                                       int frames_per_buffer)
+    : sample_rate_(sample_rate), frames_per_buffer_(frames_per_buffer) {}
 
 MockWebAudioDevice::~MockWebAudioDevice() {}
 
 void MockWebAudioDevice::start() {}
 
 void MockWebAudioDevice::stop() {}
 
 double MockWebAudioDevice::sampleRate() {
   return sample_rate_;
 }
 
+int MockWebAudioDevice::framesPerBuffer() {
+  return frames_per_buffer_;
+}
+
 }  // namespace test_runner