how to add WebControl to my page layout

Question

I want to add the following code to my page layout to fix a bug in SharePoint 2013:-

[ToolboxData("<{0}:CustomValidationRequiredFieldsOnPage runat=server></{0}:CustomValidationRequiredFieldsOnPage>")]
public class CustomValidationRequiredFieldsOnPage : WebControl
{
 protected override void CreateChildControls()
 {
 base.CreateChildControls();

 if (SPContext.Current.FormContext.FormMode == SPControlMode.Edit)
 {
  bool arethere = AreThereAnyMissingRequiredFieldsOnPage();

  if (arethere)
  {
   //SPPageStateControl:
   //Provides an ASP.NET control that handles the Ribbon buttons controlling the state of a Microsoft SharePoint Server wiki or publishing page,
   //such as the CheckInCheckOutButton or the PublishingButton.
   SPPageStateControl baseParentStateControl = Page.Items[typeof(SPPageStateControl)] as SPPageStateControl;

   //Publish button: SPListItem MissingRequiredFields checks this.FieldHasValue(link.Name, field);
   //the field is empty (which is right) when the page is first created (MMD field is never filled in)
   //when the field was once filled, saved and emptied the field in sp code still has the previous value and the check MissingRequiredFields succeeds
   //after succeeding this check the page is validated (this.Page.Validate()) and this one fails which results SP validating the page as the Save button does

   if (baseParentStateControl.HasError)
   {
    //this overwrites the previous PageErrorState
    //and validates the page
    //no popup anymore and status updates in yellow area
    baseParentStateControl.EnsureItemSavedIfEditMode(false);
   }
  }
  else
  {
   //there are missing fields at this listitem, but they're not on the page
   //do nothing here, because the SerializedErrorState contains the navigate url to the Edit Properties page
   //and a message pops up
  }
 }
}

 /// <summary>
 /// Check if required fields are missing which are present at the page
 /// </summary>
 /// <returns></returns>
 private static bool AreThereAnyMissingRequiredFieldsOnPage()
 {
  foreach (Control control in SPContext.Current.FormContext.FieldControlCollection)
  {
   //get the control type
   string type = control.GetType().Name;

   FieldTypes controlType = (FieldTypes)Enum.Parse(typeof(FieldTypes), type);

   switch (controlType)
   {
    case FieldTypes.TaxonomyFieldControl:
     TaxonomyFieldControl tfc = control as TaxonomyFieldControl;
     if (!tfc.IsValid)
     {
      return true;
     }
     break;
    default:
     break;
   }
 }

 return false;
}

 enum FieldTypes
 {
 DateTimeField, FieldValue, TextField, RichImageField, NoteField, RichHtmlField, PublishingScheduleFieldControl, TaxonomyFieldControl, BooleanField, ComputedField
 }
}

but can anyone adivce , how i can add this code to my page layout , either using SP designer or visual studio ? Thanks