Workaround for Unity set Screen.orientation bug on iOS 10.

ForceLandscape.cs

using UnityEngine;
using System.Collections;

// This is used to workaround https://issuetracker.unity3d.com/issues/ios-changing-the-screen-orientation-via-a-script-sometimes-results-in-corrupted-view-on-ios-10
// Bug shows screen in portrait with content rotated 90 offscreen. Caused by explicitly setting Landscape orientation on iOS 10.
// 
// On iOS this just switches to LandscapeLeft, back to Portrait, and then back to LandscapeLeft, which seems to work.
// SUGGESTION: blank out the screen before executing this, since the screen jumps around as it switches back and forth.
public class ForceLandscape : MonoBehaviour
{
    public void ForceLandscapeLeft()
    {
        #if UNITY_IOS && !UNITY_EDITOR
        StartCoroutine(ForceAndFixLandscape());
        #else
        Screen.orientation = ScreenOrientation.LandscapeLeft;
        #endif
    }

    IEnumerator ForceAndFixLandscape()
    {
        ScreenOrientation prev = ScreenOrientation.Portrait;
        for (int i = 0; i < 3; i++)
        {
            Screen.orientation = 
                (prev == ScreenOrientation.Portrait ? ScreenOrientation.LandscapeLeft : ScreenOrientation.Portrait);
            yield return new WaitWhile(() => {
                return prev == Screen.orientation;
            });
            prev = Screen.orientation; 
            yield return new WaitForSeconds(0.5f); //this is an arbitrary wait value -- it may need tweaking for different iPhones!
        }
    }
    
}