The scene is not rendered when all the Post processing effects are disabled on WebGL/Facebook WebGL player built using OpenGLES 3.0

Steps to repro:
1. Open attached project.(postprocessing scene from Shinai project)
2. File > Build Settings > Select WebGL/Facebook WebGL > Switch Platform.
3. Player Settings > Other Settings > Uncheck Auto Graphics API.
4. Select OpenGLES3 in Graphics APIs list.
5. Click on Build And Run.

Observe that,
-with all options enabled the scene is partially rendered with high contrast and bleached out.
-with all options disabled the scene is completely bleached out.

NOTE: Refer the videos attached.

Expected Result:
The scene should be rendered all the assets.(Refer screenshot attached)

Reproducible on: 2018.1.0b12, 2018.1.0b11, 2018.1.0b1, 2017.3.0f3.

Works fine on: 2017.2.0f3.

Environment:
Windows 10, Windows7, Mac 10.13, Mac 10.12.