Fixed a bug in relative margins on Android

[hanachiru]

summary

When doing SetMargins with relative true on android, the margins are incorrect.

On Android, Screen.width(height) always returns the same value as Screen.currentResolution.width(height).
So, whether relative is true or false, ml, mt, mr, and mb use the same value.

unity-webview/plugins/WebViewObject.cs

Lines 824 to 841 in 09f1925

	if (relative)
	{
	float w = (float)Screen.width;
	float h = (float)Screen.height;
	int iw = Screen.currentResolution.width;
	int ih = Screen.currentResolution.height;
	ml = left / w * iw;
	mt = top / h * ih;
	mr = right / w * iw;
	mb = AdjustBottomMargin((int)(bottom / h * ih));
	}
	else
	{
	ml = left;
	mt = top;
	mr = right;
	mb = AdjustBottomMargin(bottom);
	}

Display.main.systemWidth(systemHeight) can be used to obtain the resolution of the physical screen.(not rendering resolution)
The argument of ViewGroup.MarginLayoutParams.setMargin, which is executed in CWebViewPlugin.java, uses px.(physical screen)
So I think this bug can be fixed by using Display.main.systemWidth(systemHeight).

unity-webview/plugins/Android/webview/src/main/java/net/gree/unitywebview/CWebViewPlugin.java

Line 1069 in 09f1925

params.setMargins(left, top, right, bottom);

How to reproduce

You can reproduce the bug by calling WebViewObject.SetMargins after using Screen.SetResolution on Android.
Display.main.systemWidth(systemHeight) instead of Screen.currentResolution.width(height) seems to correctly convert from the value on the rendering resolution to the value on the physical resolution(px).

cf

https://docs.unity3d.com/ScriptReference/Display-systemWidth.html
https://developer.android.com/reference/android/view/ViewGroup.MarginLayoutParams#attr_android:layout_margin
https://docs.unity3d.com/ScriptReference/Screen.SetResolution.html

[KojiNakamaru]

Thank you for the fix with detailed analysis. As I noticed that Display.main.{systemWith,systemHeight} didn't reflect the navigation bar's margin, I'll later extend your code after merging this pull request.