Differentiating between mobile and WebGL

Searching for a way to differentiate between GLES2 mobile and GLES2 WebGL in my shaders so that I can treat them as different quality levels. In Unity 5.3 they had a pre-processor macro called UNITY_53_SPECIFIC_TARGET_WEBGL that handled this. With 5.4 this has gone away and they are setting all the Standard Shader quality settings through the editor when switching build targets. The pre-processor macro SHADER_API_GLES wont work since that gets triggered for both mobile and WebGL. Any ideas?

 

Also SHADER_API_GLES is not set within Unity Editor, so there's no way to detect WebGL build in shaders.