Use enum class for subtypes of CPDF_Annot.

fpdfsdk/formfiller/cffl_formfiller.cpp

 // Copyright 2014 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #include "fpdfsdk/formfiller/cffl_formfiller.h"
 
 #include "core/fpdfapi/fpdf_page/include/cpdf_page.h"
 #include "core/fxge/include/cfx_renderdevice.h"
@@ skipping 67 matching lines @@
   CFX_FloatRect rect = CPWL_Utils::InflateRect(rcWin, 1);
 
   return rect.GetOuterRect();
 }
 
 void CFFL_FormFiller::OnDraw(CPDFSDK_PageView* pPageView,
                              CPDFSDK_Annot* pAnnot,
                              CFX_RenderDevice* pDevice,
                              CFX_Matrix* pUser2Device,
                              uint32_t dwFlags) {
-  ASSERT(pAnnot->GetPDFAnnot()->GetSubtype() == "Widget");
+  ASSERT(pAnnot->GetPDFAnnot()->GetSubtype() == CPDF_Annot::Subtype::WIDGET);
 
   if (CPWL_Wnd* pWnd = GetPDFWindow(pPageView, FALSE)) {
     CFX_Matrix mt = GetCurMatrix();
     mt.Concat(*pUser2Device);
     pWnd->DrawAppearance(pDevice, &mt);
   } else {
     CPDFSDK_Widget* pWidget = (CPDFSDK_Widget*)pAnnot;
     if (CFFL_IFormFiller::IsVisible(pWidget))
       pWidget->DrawAppearance(pDevice, pUser2Device, CPDF_Annot::Normal,
                               nullptr);
@@ skipping 618 matching lines @@
   }
 }
 
 void CFFL_Button::OnDrawDeactive(CPDFSDK_PageView* pPageView,
                                  CPDFSDK_Annot* pAnnot,
                                  CFX_RenderDevice* pDevice,
                                  CFX_Matrix* pUser2Device,
                                  uint32_t dwFlags) {
   OnDraw(pPageView, pAnnot, pDevice, pUser2Device, dwFlags);
 }