vp9: Enable vp9 denoiser by default in standalone webrtc.

webrtc/modules/video_coding/codecs/vp9/vp9_impl.cc

Index: webrtc/modules/video_coding/codecs/vp9/vp9_impl.cc
diff --git a/webrtc/modules/video_coding/codecs/vp9/vp9_impl.cc b/webrtc/modules/video_coding/codecs/vp9/vp9_impl.cc
index 4d7df867a27196afaa115ca72c69ac13d0df7ea2..c7191aa6617b5a4070962df728b2494a6fa549e8 100644
--- a/webrtc/modules/video_coding/codecs/vp9/vp9_impl.cc
+++ b/webrtc/modules/video_coding/codecs/vp9/vp9_impl.cc
@@ -452,13 +452,15 @@ int VP9EncoderImpl::InitAndSetControlSettings(const VideoCodec* inst) {
 
   // Turn on row-based multithreading.
   vpx_codec_control(encoder_, VP9E_SET_ROW_MT, 1);
+
 #if !defined(WEBRTC_ARCH_ARM) && !defined(WEBRTC_ARCH_ARM64) && \
   !defined(ANDROID)
-  // Note denoiser is still off by default until further testing/optimization,
-  // i.e., VP9().denoisingOn == 0.
+  // Turn off the denoiser on ARM since optimization is pending.

[brandtr, 2017/05/29 07:14:35]

Nit: "Do not enable the denoiser..."

(Since you are actively not turning it on, not actively turning it off.)

[jianj, 2017/06/05 17:26:05]

Done.

+  // Denoiser is on by default on other platforms.
   vpx_codec_control(encoder_, VP9E_SET_NOISE_SENSITIVITY,
                     inst->VP9().denoisingOn ? 1 : 0);
 #endif
+
   if (codec_.mode == kScreensharing) {
     // Adjust internal parameters to screen content.
     vpx_codec_control(encoder_, VP9E_SET_TUNE_CONTENT, 1);