Add method cricket::VideoCapturer::NeedsDenoising, use in VideoCapturerTrackSource.

webrtc/api/videocapturertracksource.cc

Index: webrtc/api/videocapturertracksource.cc
diff --git a/webrtc/api/videocapturertracksource.cc b/webrtc/api/videocapturertracksource.cc
index 1bf4bea1d0d779ec93eff06e55b73f1ebd998572..dd9b54872b196303d8c2a1f2b27963d019fe5158 100644
--- a/webrtc/api/videocapturertracksource.cc
+++ b/webrtc/api/videocapturertracksource.cc
@@ -320,6 +320,10 @@ void VideoCapturerTrackSource::Initialize(
     }
   }
 
+  // Get default from the capturer, overridden by constraints, if any.
+  // Note that Chrome no longer uses the webrtc constraints interface.
+  needs_denoising_ = video_capturer_->NeedsDenoising();
+
   if (constraints) {
     MediaConstraintsInterface::Constraints mandatory_constraints =
         constraints->GetMandatory();