GC with Image in unsupported use cases

Logging a warning for GC initialized with unsupported use cases.
1. all dynamic images (retrieved via any of the existing providers).
2. all images for which handles in other zoom values have already been
created.

Author: ShahzaibIbrahim

bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/graphics/Image.java

@@ -26,6 +26,7 @@
 import org.eclipse.swt.internal.gdip.*;
 import org.eclipse.swt.internal.image.*;
 import org.eclipse.swt.internal.win32.*;
+import org.eclipse.swt.widgets.Display;
 
 /**
  * Instances of this class are graphics which have been prepared
@@ -1690,6 +1691,18 @@ private ImageHandle init(ImageData i, int zoom) {
 	}
 }
 
+private void assertCondition(boolean condition, String message) {
+    if (condition) {
+        RuntimeException ex = new RuntimeException("Assertion failed: " + message);
+        Display display = Display.getCurrent();
+        if (display != null && display.getRuntimeExceptionHandler() != null) {
+            display.getRuntimeExceptionHandler().accept(ex);
+        } else {
+            throw ex;
+        }
+    }
+}
+
 /**
  * Invokes platform specific functionality to allocate a new GC handle.
  * <p>
@@ -1716,6 +1729,9 @@ public long internal_new_GC (GCData data) {
 		SWT.error(SWT.ERROR_INVALID_ARGUMENT);
 	}
 
+	assertCondition(imageProvider != null && (imageProvider instanceof ImageDataProviderWrapper || imageProvider instanceof ImageFileNameProviderWrapper), "Image initialized with ImageDataProvider or ImageFileNameProvider is not supposed to be modified");
+	assertCondition(!zoomLevelToImageHandle.isEmpty() && (zoomLevelToImageHandle.size() != 1 || !zoomLevelToImageHandle.containsKey(getZoom())), "Images with handles created for a different zoom level should not be modified");
+
 	/* Create a compatible HDC for the device */
 	long hDC = device.internal_new_GC(null);
 	long imageDC = OS.CreateCompatibleDC(hDC);