cast: Support for low-latency interactive mode

chrome/renderer/extensions/cast_streaming_native_handler.cc

Index: chrome/renderer/extensions/cast_streaming_native_handler.cc
diff --git a/chrome/renderer/extensions/cast_streaming_native_handler.cc b/chrome/renderer/extensions/cast_streaming_native_handler.cc
index b861f826433541592083c3cb3a1aa66b187e8348..7d1716c49a4a75242c7a7754ee9a701fd6572dd5 100644
--- a/chrome/renderer/extensions/cast_streaming_native_handler.cc
+++ b/chrome/renderer/extensions/cast_streaming_native_handler.cc
@@ -89,6 +89,9 @@ bool ToCastRtpPayloadParamsOrThrow(v8::Isolate* isolate,
   cast_params->max_latency_ms = ext_params.max_latency;
   cast_params->min_latency_ms =
       ext_params.min_latency ? *ext_params.min_latency : ext_params.max_latency;
+  cast_params->animated_latency_ms = ext_params.animated_latency
+                                         ? *ext_params.animated_latency
+                                         : ext_params.max_latency;

[miu, 2015/12/03 21:26:22]

I think the "else" clause of this expression will return nullptr casted to a
zero integer.  Instead, should we just use a default, bounded within min and
max?  Something like:

  if (cast_params->min_latency_ms > cast_params->max_latency_ms)
    return false;

  ...

  if (cast_params->min_latency_ms <= 0) {
    cast_params->animated_latency_ms = max_latency_ms;
  } else {
    cast_params->animated_latency_ms =
        std::min(cast_params->max_latency_ms,
std::max(cast_params->min_latency_ms, kDefaultAnimatedLatencyMillis));
  }

[Irfan, 2015/12/04 22:45:36]

The else part of the expression is returning an int. max_latency is a mandatory
parameter (and hence an int). If there are no animation/min params passed, they
default to the max value.

[miu, 2015/12/08 00:16:16]

Acknowledged.

   cast_params->codec_name = ext_params.codec_name;
   cast_params->ssrc = ext_params.ssrc;
   cast_params->feedback_ssrc = ext_params.feedback_ssrc;
@@ -126,6 +129,7 @@ void FromCastRtpPayloadParams(const CastRtpPayloadParams& cast_params,
   ext_params->payload_type = cast_params.payload_type;
   ext_params->max_latency = cast_params.max_latency_ms;
   ext_params->min_latency.reset(new int(cast_params.min_latency_ms));
+  ext_params->animated_latency.reset(new int(cast_params.animated_latency_ms));
   ext_params->codec_name = cast_params.codec_name;
   ext_params->ssrc = cast_params.ssrc;
   ext_params->feedback_ssrc = cast_params.feedback_ssrc;