Use proper classloader for finding SVGRasterizer #1965 #2049

When initializing the SVGFileFormat class for loading SVGs, the current
context classloader is used by the ServiceLoader to find an
SVGRasterizer implementation. This classloader may be incorrect in some
cases, i.e., it may not be the plain system classloader or an according
OSGi classloader but, e.g., some specific classloader for test
execution.

This change makes the ServiceLoader use the same classloader for finding
an SVGRasterizer implementation than the classloader of the
SVGRasterizer class itself.

Fixes #1965

Fixes #2049

Author: HeikoKlare

bundles/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/internal/image/SVGFileFormat.java

@@ -31,7 +31,11 @@
 public class SVGFileFormat extends FileFormat {
 
 	/** The instance of the registered {@link SVGRasterizer}. */
-	private static final SVGRasterizer RASTERIZER = ServiceLoader.load(SVGRasterizer.class).findFirst().orElse(null);
+	// The service loader uses the classloader of the SVGRasterizer class to avoid
+	// that a potentially non-fitting context classloader is used for searching for
+	// a rasterizer implementation (such as during test execution).
+	private static final SVGRasterizer RASTERIZER = ServiceLoader
+			.load(SVGRasterizer.class, SVGRasterizer.class.getClassLoader()).findFirst().orElse(null);
 
 	@Override
 	boolean isFileFormat(LEDataInputStream stream) throws IOException {