Remove header files that only have includes.

fpdfsdk/src/pdfwindow/PWL_ComboBox.cpp

Index: fpdfsdk/src/pdfwindow/PWL_ComboBox.cpp
diff --git a/fpdfsdk/src/pdfwindow/PWL_ComboBox.cpp b/fpdfsdk/src/pdfwindow/PWL_ComboBox.cpp
index e92d936d46e9bcf46dab76b35c16a944f66e387d..392867c29aaeabc1c1e37e102b6d2a60d641f817 100644
--- a/fpdfsdk/src/pdfwindow/PWL_ComboBox.cpp
+++ b/fpdfsdk/src/pdfwindow/PWL_ComboBox.cpp
@@ -4,13 +4,14 @@
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
-#include "fpdfsdk/include/pdfwindow/PDFWindow.h"
 #include "fpdfsdk/include/pdfwindow/PWL_ComboBox.h"
+
 #include "fpdfsdk/include/pdfwindow/PWL_Edit.h"
 #include "fpdfsdk/include/pdfwindow/PWL_EditCtrl.h"
 #include "fpdfsdk/include/pdfwindow/PWL_ListBox.h"
 #include "fpdfsdk/include/pdfwindow/PWL_Utils.h"
 #include "fpdfsdk/include/pdfwindow/PWL_Wnd.h"
+#include "public/fpdf_fwlevent.h"
 
 #define PWLCB_DEFAULTFONTSIZE 12.0f
 
@@ -19,8 +20,6 @@
 #define IsFloatSmaller(fa, fb) ((fa) < (fb) && !IsFloatZero((fa) - (fb)))
 #define IsFloatEqual(fa, fb) IsFloatZero((fa) - (fb))
 
-/* ---------------------------- CPWL_CBListBox ---------------------------- */
-
 FX_BOOL CPWL_CBListBox::OnLButtonUp(const CPDF_Point& point, FX_DWORD nFlag) {
   CPWL_Wnd::OnLButtonUp(point, nFlag);
 
@@ -108,8 +107,6 @@ FX_BOOL CPWL_CBListBox::OnCharWithExit(FX_WORD nChar,
   return TRUE;
 }
 
-/* ---------------------------- CPWL_CBButton ---------------------------- */
-
 void CPWL_CBButton::GetThisAppearanceStream(CFX_ByteTextBuf& sAppStream) {
   CPWL_Wnd::GetThisAppearanceStream(sAppStream);
 
@@ -199,8 +196,6 @@ FX_BOOL CPWL_CBButton::OnLButtonUp(const CPDF_Point& point, FX_DWORD nFlag) {
   return TRUE;
 }
 
-/* ---------------------------- CPWL_ComboBox ---------------------------- */
-
 CPWL_ComboBox::CPWL_ComboBox()
     : m_pEdit(NULL),
       m_pButton(NULL),