Support AudioContextOptions latencyHint as double.

content/renderer/media/renderer_webaudiodevice_impl.cc

Index: content/renderer/media/renderer_webaudiodevice_impl.cc
diff --git a/content/renderer/media/renderer_webaudiodevice_impl.cc b/content/renderer/media/renderer_webaudiodevice_impl.cc
index 2c4f81b185d74fe96ab0a25d677a67fd0d3d9296..764a26345747e54d592ff2a45b2197e301676306 100644
--- a/content/renderer/media/renderer_webaudiodevice_impl.cc
+++ b/content/renderer/media/renderer_webaudiodevice_impl.cc
@@ -41,8 +41,7 @@ AudioDeviceFactory::SourceType GetLatencyHintSourceType(
     case WebAudioLatencyHint::kCategoryPlayback:
       return AudioDeviceFactory::kSourceWebAudioPlayback;
     case WebAudioLatencyHint::kCategoryExact:
-      // TODO implement CategoryExact
-      return AudioDeviceFactory::kSourceWebAudioInteractive;
+      return AudioDeviceFactory::kSourceWebAudioExact;
   }
   NOTREACHED();
   return AudioDeviceFactory::kSourceWebAudioInteractive;
@@ -128,7 +127,13 @@ RendererWebAudioDeviceImpl::RendererWebAudioDeviceImpl(
           hardware_params.sample_rate(), 0);
       break;
     case media::AudioLatency::LATENCY_EXACT_MS:
-    // TODO(olka): add support when WebAudio requires it.
+      output_buffer_size = output_buffer_size =

[o1ka, 2017/03/16 10:51:23]

extra "output_buffer_size ="?

[Andrew MacPherson, 2017/03/16 17:02:09]

Oops, fixed!

+          media::AudioLatency::GetExactBufferSize(
+              latency_hint.seconds() * hardware_params.sample_rate(),
+              media::AudioLatency::GetHighLatencyBufferSize(
+                  hardware_params.sample_rate(), 0),
+              hardware_params.frames_per_buffer());

[o1ka, 2017/03/16 10:51:24]

Can it be GetExactBufferSize(duration, hardware_params)?

[Andrew MacPherson, 2017/03/16 17:02:09]

Done.

+      break;
     default:
       NOTREACHED();
   }