Can Tensorflow be used to detect if a particular feature exists in an image?
Yes and no. Tensorflow is a graph computation library mostly suited for neural networks. 
You can create a neural network that determines if a face is in the image or not... You can even search for existing implementations that use Tensorflow...
There is no default Haar feature based cascade classifier in Tensorflow...
For example, using OpenCV and haarcascade_frontal_face.xml, we can predict if a face exists in an image. I would like to know if such a thing (detecting an object of interest) is possible with Tensorflow and if yes, how?