mdContactChips: add option to specify default image

[Frank3K]

In the current implementation of md-contact-chips one can specify the field name of the image corresponding to a contact using the md-contact-image attribute.

However, when a given contact does not have set that field (i.e. the contact does not have an image), an empty <img /> tag is rendered. Since an alt-attribute is added to the image some browsers (at least Chromium on Linux) render the image as wide as the contents of the alt-attribute. This messes with the layout of the contact chips.

It would be nice if there was a way to specify a default image, which is used in case there is no corresponding image. Another (slightly inferior) option would be to not render the <img /> at all.

[topherfangio]

I think this is a good idea, but as a workaround, you can handle this at the "model" layer by making sure the data returns something useful when null.

I typically handle this at the JS model or even server layer (usually Ruby on Rails) so that I can use existing model data to dynamically change the URL based on that particular user (i.e. different pictures for male/female, etc).

[Frank3K]

I also thought of solving the issue in the model layer, but I thought a solution in the contact chips itself would be easier for the developer.

Do you think it is a good idea to hide the image if not image has been provided at all? I think I can work out a PR for that.

[topherfangio]

If you can find a solution that replaces the image with something of the same size (and maybe even an icon), I think that might work well.