Adding method IsInBeam to beamformer class.

webrtc/modules/audio_processing/beamformer/nonlinear_beamformer.cc

Index: webrtc/modules/audio_processing/beamformer/nonlinear_beamformer.cc
diff --git a/webrtc/modules/audio_processing/beamformer/nonlinear_beamformer.cc b/webrtc/modules/audio_processing/beamformer/nonlinear_beamformer.cc
index 1e03c853fe05909eb4a98251b1c8b097578301f9..e466100cb0ade4cee2b038413a342b7304def945 100644
--- a/webrtc/modules/audio_processing/beamformer/nonlinear_beamformer.cc
+++ b/webrtc/modules/audio_processing/beamformer/nonlinear_beamformer.cc
@@ -50,6 +50,8 @@ const float kInterfAngleRadians = static_cast<float>(M_PI) / 4.f;
 // Rpsi = Rpsi_angled * kBalance + Rpsi_uniform * (1 - kBalance)
 const float kBalance = 0.4f;
 
+const float kHalfBeamWidthRadians = static_cast<float>(M_PI) * 20.f / 180.f;
+
 // TODO(claguna): need comment here.
 const float kBeamwidthConstant = 0.00002f;
 
@@ -334,6 +336,13 @@ void NonlinearBeamformer::ProcessChunk(const ChannelBuffer<float>& input,
   }
 }
 
+bool NonlinearBeamformer::IsInBeam(SphericalPointf spherical_point) {
+  // If more than half-beamwidth degrees away from the beam's center,
+  // you are out of the beam.
+  return fabs(spherical_point.azimuth() - kTargetAngleRadians) <
+         kHalfBeamWidthRadians;
+}
+
 void NonlinearBeamformer::ProcessAudioBlock(const complex_f* const* input,
                                             int num_input_channels,
                                             int num_freq_bins,