How to render OES Texture in Unity

I am trying to render an OES texture in Unity. I create the texture on Java side and then interop that to Unity. Here is my Unity code:

             m_currentTexture = Texture2D.CreateExternalTexture(1080, 1920, TextureFormat.RGB24, false, false, new System.IntPtr(webviewTextureReference));
             bool hasMainTexProp = GetComponent<Renderer>().material.HasProperty("_MainTex");
             print("texture hasproperty: " + hasMainTexProp);
             GetComponent<Renderer>().material.EnableKeyword("_MainTex");
             GetComponent<Renderer>().material.SetTexture("_MainTex", m_currentTexture);

And my fragment shader:

             #ifdef FRAGMENT
             #extension GL_OES_EGL_image_external : require
             uniform samplerExternalOES _MainTex;
             varying vec2 TextureCoordinate;
             void main()
             {
                 gl_FragColor = textureExternal(_MainTex, TextureCoordinate);
             }
             #endif

Any ideas? Only black renders.