added an async version of MarkContentDirty(), which would clear the backgrounds in case an expose event had already happened earlier, however, it turned out I didn't need it yet, see next commit

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@17510 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/servers/app/WindowLayer.cpp

@@ -676,6 +676,24 @@ WindowLayer::MarkContentDirty(BRegion& regionOnScreen)
 }
 
 
+void
+WindowLayer::MarkContentDirtyAsync(BRegion& regionOnScreen)
+{
+	// NOTE: see comments in ProcessDirtyRegion()
+	if (fHidden)
+		return;
+
+	regionOnScreen.IntersectWith(&VisibleContentRegion());
+
+	if (fDirtyRegion.CountRects() == 0) {
+		ServerWindow()->RequestRedraw();
+	}
+
+	fDirtyRegion.Include(&regionOnScreen);
+	fDirtyCause |= UPDATE_REQUEST;
+}
+
+
 void
 WindowLayer::InvalidateView(ViewLayer* layer, BRegion& layerRegion)
 {

src/servers/app/WindowLayer.h

@@ -99,8 +99,9 @@ class WindowLayer {
 			// can be used from inside classes that don't
 			// need to know about Desktop (first version uses Desktop)
 			void				MarkDirty(BRegion& regionOnScreen);
-			// this version does not use the Desktop
+			// these versions do not use the Desktop
 			void				MarkContentDirty(BRegion& regionOnScreen);
+			void				MarkContentDirtyAsync(BRegion& regionOnScreen);
 			// shortcut for invalidating just one view
 			void				InvalidateView(ViewLayer* view, BRegion& layerRegion);