Make OS audio buffer size limits visible.

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 ef941bec24e00b4c414f38abd6562ecf39c08ba3..e09e0d7919ca26410a9b2b3e79e1b5ad2b4d706f 100644
--- a/content/renderer/media/renderer_webaudiodevice_impl.cc
+++ b/content/renderer/media/renderer_webaudiodevice_impl.cc
@@ -65,12 +65,13 @@ int GetOutputBufferSize(const blink::WebAudioLatencyHint& latency_hint,
           hardware_params.sample_rate(), 0);
       break;
     case media::AudioLatency::LATENCY_EXACT_MS:
-      // TODO(andrew.macpherson@soundtrap.com): http://crbug.com/708917
-      return std::min(4096,

[Raymond Toy, 2017/05/30 18:05:57]

Can't remember the actual value, but make this consistent with the playback
latency value.  The user should be able to specify a value up to the playback
latency.  Perhaps even using GetHighLatencyBufferSize to figure this out.

+      return std::min(media::AudioLatency::GetMaximumAudioBufferSize(
+                          hardware_params.sample_rate()),
                       media::AudioLatency::GetExactBufferSize(
                           base::TimeDelta::FromSecondsD(latency_hint.Seconds()),
                           hardware_params.sample_rate(),
-                          hardware_params.frames_per_buffer()));
+                          media::AudioLatency::GetMinimumAudioBufferSize(
+                              hardware_params.sample_rate())));
       break;
     default:
       NOTREACHED();