LibWeb: Implement CanvasRenderingContext2D.restore()

Author: https://github.com/linusg
Commit: 3e0e965f24
Pull-request: https://github.com/SerenityOS/serenity/pull/11444

Userland/Libraries/LibWeb/HTML/CanvasRenderingContext2D.cpp

@@ -320,4 +320,13 @@ void CanvasRenderingContext2D::save()
     m_drawing_state_stack.append(m_drawing_state);
 }
 
+// https://html.spec.whatwg.org/multipage/canvas.html#dom-context-2d-restore
+void CanvasRenderingContext2D::restore()
+{
+    // The restore() method steps are to pop the top entry in the drawing state stack, and reset the drawing state it describes. If there is no saved state, then the method must do nothing.
+    if (m_drawing_state_stack.is_empty())
+        return;
+    m_drawing_state = m_drawing_state_stack.take_last();
+}
+
 }