Help with Unity WebGL feature that doesn't work in Chrome

I'm the owner of a website that offers a Unity application to therapists for using with clients. (http://www.simplysandplay.com) We have not been able to get certain features to work in Google Chrome. Right now we tell our users to use Firefox instead.

The feature that doesn't work is the water drawing tool which you can see in this video. https://www.youtube.com/watch?v=Yin666T8pcg&t=2s

Here is the issue as explained to me by our developer:
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Here is the code that doesn't work on Chrome,

RenderTexture temp = RenderTexture.GetTemporary(splatMap.width, splatMap.width, 1, splatMap.format);

Graphics.Blit(splatMap, temp);

Graphics.Blit(temp, splatMap, drawMaterial);
RenderTexture.ReleaseTemporary(temp);

What's happening here is copying the data from the sand Texture and storing it and then saving it back to itself with the addition of the user input. My understanding of why this doesn't work in chrome is because they have a rendering check, which prevents a texture from copying into itself. This behaviour is indicative of an infinite loop which is why they probably don't allow for it but it is also necessary to do this to update a texture.
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I'm looking for someone who will be able to provide a solution. You may need to develop a simple Unity game that has no other elements other than changing one texture into another using a mouse as seen in the video of our application. Your sample game will need to work in Chrome and Firefox.