public Builder clearRollAngle() {
      bitField0_ = (bitField0_ & ~0x00000008);
      rollAngle_ = 0F;
      onChanged();
      return this;
    }
<pre>
Roll angle, which indicates the amount of clockwise/anti-clockwise rotation
of the face relative to the image vertical about the axis perpendicular to
the face. Range [-180,180].
</pre>

<code>float roll_angle = 4;</code>

@return This builder for chaining.
java-vision/proto-google-cloud-vision-v1p1beta1/src/main/java/com/google/cloud/vision/v1p1beta1/FaceAnnotation.java