CPWL_Color::ConvertColorType should compare current color type with the given convert color type.

fpdfsdk/pdfwindow/PWL_Utils.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/pdfwindow/PWL_Utils.h"
 
 #include <algorithm>
 
@@ skipping 3290 matching lines @@
       CPWL_PathData(CPWL_Point(crInBox.left + fWidth * 0.90f, crInBox.top),
                     PWLPT_LINETO),
   };
 
   if (type == PWLPT_STREAM)
     sPathData = GetAppStreamFromArray(PathArray, 23);
   else
     GetPathDataFromArray(path, PathArray, 23);
 }
 
-void CPWL_Color::ConvertColorType(int32_t other_nColorType) {
-  switch (other_nColorType) {
+void CPWL_Color::ConvertColorType(int32_t nConvertColorType) {
+  if (nColorType == nConvertColorType)
+    return;
+
+  switch (nColorType) {

[dsinclair, 2016/09/09 00:09:26]

Are we sure nColorType is the correct item for the outer switch? It's hard to
tell from reading the code if the colour we're going too should be here, or the
colour we're going from.

[jaepark, 2016/09/09 00:39:41]

Since the inner switch is calling functions OUTER2INNER, I think the color we're
going from is in the outer switch.

     case COLORTYPE_TRANSPARENT:
       break;
     case COLORTYPE_GRAY:
-      switch (other_nColorType) {
+      switch (nConvertColorType) {
         case COLORTYPE_RGB:
           CPWL_Utils::ConvertGRAY2RGB(fColor1, fColor1, fColor2, fColor3);
           break;
         case COLORTYPE_CMYK:
           CPWL_Utils::ConvertGRAY2CMYK(fColor1, fColor1, fColor2, fColor3,
                                        fColor4);
           break;
       }
       break;
     case COLORTYPE_RGB:
-      switch (other_nColorType) {
+      switch (nConvertColorType) {
         case COLORTYPE_GRAY:
           CPWL_Utils::ConvertRGB2GRAY(fColor1, fColor2, fColor3, fColor1);
           break;
         case COLORTYPE_CMYK:
           CPWL_Utils::ConvertRGB2CMYK(fColor1, fColor2, fColor3, fColor1,
                                       fColor2, fColor3, fColor4);
           break;
       }
       break;
     case COLORTYPE_CMYK:
-      switch (other_nColorType) {
+      switch (nConvertColorType) {
         case COLORTYPE_GRAY:
           CPWL_Utils::ConvertCMYK2GRAY(fColor1, fColor2, fColor3, fColor4,
                                        fColor1);
           break;
         case COLORTYPE_RGB:
           CPWL_Utils::ConvertCMYK2RGB(fColor1, fColor2, fColor3, fColor4,
                                       fColor1, fColor2, fColor3);
           break;
       }
       break;
   }
-  nColorType = other_nColorType;
+  nColorType = nConvertColorType;
 }