Add ElementPropertyContainer#setHeightPercent() method.

Unignore test.

DEVSIX-1658

Author: pavel-alay

layout/src/main/java/com/itextpdf/layout/ElementPropertyContainer.java

@@ -188,6 +188,17 @@ public T setHeight(float height) {
         return (T) (Object) this;
     }
 
+    /**
+     * Sets the height property of the Element, measured in percentage.
+     *
+     * @param heightPercent a value measured in percentage.
+     * @return this Element.
+     */
+    public T setHeightPercent(float heightPercent) {
+        setProperty(Property.HEIGHT, UnitValue.createPercentValue(heightPercent));
+        return (T) (Object) this;
+    }
+
     /**
      * Sets the width property of the Element with a {@link UnitValue}.
      *
@@ -198,6 +209,7 @@ public T setHeight(UnitValue height) {
         setProperty(Property.HEIGHT, height);
         return (T) (Object) this;
     }
+
     /**
      * Sets values for a relative repositioning of the Element. Also has as a
      * side effect that the Element's {@link Property#POSITION} is changed to

layout/src/test/java/com/itextpdf/layout/ImageTest.java

@@ -494,7 +494,8 @@ public void imageTest18() throws IOException, InterruptedException {
 
         Assert.assertNull(new CompareTool().compareByContent(outFileName, cmpFileName, destinationFolder, "diff"));
     }
-    @Ignore("DEVSIX-1658")
+
+    //TODO(DEVSIX-1658)
     @Test
     public void imageTest19() throws IOException, InterruptedException {
         String outFileName = destinationFolder + "imageTest19.pdf";