Support for AudioContextOptions latencyHint.

components/test_runner/mock_web_audio_device.cc

Index: components/test_runner/mock_web_audio_device.cc
diff --git a/components/test_runner/mock_web_audio_device.cc b/components/test_runner/mock_web_audio_device.cc
index 6788d86b6fc27d04bb2842c2d1fbfa83547aaf43..bfd83fe47131a884218e9fda76bae15f58432b26 100644
--- a/components/test_runner/mock_web_audio_device.cc
+++ b/components/test_runner/mock_web_audio_device.cc
@@ -6,8 +6,9 @@
 
 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() {}
 
@@ -19,4 +20,8 @@ double MockWebAudioDevice::sampleRate() {
   return sample_rate_;
 }
 
+int MockWebAudioDevice::framesPerBuffer() {
+  return frames_per_buffer_;
+}
+
 }  // namespace test_runner