SurfaceTest: destroy GL context immediately after use (#407)

Use abandon before destroy

skiko/src/commonMain/kotlin/org/jetbrains/skia/DirectContext.kt

 package org.jetbrains.skia
 
+import org.jetbrains.skia.impl.*
 import org.jetbrains.skia.impl.Library.Companion.staticLoad
-import org.jetbrains.skia.impl.NativePointer
-import org.jetbrains.skia.impl.RefCnt
-import org.jetbrains.skia.impl.Stats
-import org.jetbrains.skia.impl.reachabilityBarrier
 
 class DirectContext internal constructor(ptr: NativePointer) : RefCnt(ptr) {
     companion object {
@@ -112,6 +109,10 @@ class DirectContext internal constructor(ptr: NativePointer) : RefCnt(ptr) {
     }
 }
 
+fun <R> DirectContext.useContext(block: (ctx: DirectContext) -> R): R = use {
+    block(this).also { abandon() }
+}
+
 @ExternalSymbolName("org_jetbrains_skia_DirectContext__1nFlush")
 private external fun DirectContext_nFlush(ptr: NativePointer): NativePointer
 

skiko/src/commonTest/kotlin/org/jetbrains/skia/SurfaceTest.kt

@@ -115,15 +115,16 @@ class SurfaceTest {
         }
 
         val pixels = TestGlContext.run {
-            val ctx = DirectContext.makeGL()
-            val imageInfo = ImageInfo.makeN32Premul(16, 16)
-            val surface = Surface.makeRenderTarget(ctx, budgeted = false, imageInfo)
-
-            surface.canvas.drawRect(
-                r = Rect(4f, 4f, 12f, 12f),
-                paint = Paint().apply { color = Color.RED }
-            )
-            Bitmap.makeFromImage(surface.makeImageSnapshot(), ctx)
+            DirectContext.makeGL().useContext { ctx ->
+                val imageInfo = ImageInfo.makeN32Premul(16, 16)
+                val surface = Surface.makeRenderTarget(ctx, budgeted = false, imageInfo)
+
+                surface.canvas.drawRect(
+                    r = Rect(4f, 4f, 12f, 12f),
+                    paint = Paint().apply { color = Color.RED }
+                )
+                Bitmap.makeFromImage(surface.makeImageSnapshot(), ctx)
+            }
         }
 
         assertEquals(Color.RED, pixels.getColor(8, 8))