Added function getWindowHandle() for JCEF support. (Fixed)

skiko/src/jvmMain/kotlin/org/jetbrains/skiko/Drawable.kt

@@ -4,6 +4,6 @@ interface Drawable {
     fun redrawLayer()
     fun updateLayer()
     fun disposeLayer()
-    val windowHandle: Int
+    val windowHandle: Long
     val contentScale: Float
 }
\ No newline at end of file

skiko/src/jvmMain/kotlin/org/jetbrains/skiko/HardwareLayer.kt

@@ -15,7 +15,7 @@ open class HardwareLayer : Canvas(), Drawable {
     external override fun redrawLayer()
     external override fun updateLayer()
     external override fun disposeLayer()
-    override val windowHandle: Int
+    override val windowHandle: Long
         external get
     override val contentScale: Float
         external get