Revert "Expose setDrawGLFunctionDetachedCallback to webview"

This reverts commit ee34ef16.

This API is no longer needed by webview since 51.0.2704.22.
So remove this API. Note that this system API has never shipped
so it's ok to simply remove it.

Original description:
> Expose setDrawGLFunctionDetachedCallback to webview
>
> Add WebViewDelegate.setDrawGLFunctionDetachedCallback system API that's
> used for webview to receive the functor detach callback.
>
> BUG: 27709981
> Change-Id: Ie6b5e445c0090a181f94fcd2ec1ea77095c9cb03

BUG: 27709981
Change-Id: I9920dbedc6a280b4a19a8715832c4d2f64a7a7be