Use CheckedNumeric for strength calculation.

core/fxge/ge/cfx_facecache.cpp

 // Copyright 2016 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 "core/fxge/include/cfx_facecache.h"
 
 #include <algorithm>
 
 #include "core/fxge/ge/fx_text_int.h"
 #include "core/fxge/include/cfx_fontmgr.h"
 #include "core/fxge/include/cfx_gemodule.h"
 #include "core/fxge/include/cfx_pathdata.h"
 #include "core/fxge/include/cfx_substfont.h"
 #include "core/fxge/include/fx_freetype.h"
+#include "third_party/base/numerics/safe_math.h"
 
 #ifdef _SKIA_SUPPORT_
 #include "third_party/skia/include/core/SkStream.h"
 #include "third_party/skia/include/core/SkTypeface.h"
 #endif
 
 namespace {
 
 void GammaAdjust(uint8_t* pData,
                  int nHeight,
@@ skipping 120 matching lines @@
   int weight = 0;
   if (bUseCJKSubFont)
     weight = pSubstFont->m_WeightCJK;
   else
     weight = pSubstFont ? pSubstFont->m_Weight : 0;
   if (pSubstFont && !(pSubstFont->m_SubstFlags & FXFONT_SUBST_MM) &&
       weight > 400) {
     uint32_t index = (weight - 400) / 10;
     if (index >= CFX_Font::kWeightPowArraySize)
       return nullptr;
-    int level = 0;
-    if (pSubstFont->m_Charset == FXFONT_SHIFTJIS_CHARSET) {
-      level =
-          CFX_Font::s_WeightPow_SHIFTJIS[index] * 2 *
-          (FXSYS_abs((int)(ft_matrix.xx)) + FXSYS_abs((int)(ft_matrix.xy))) /
-          36655;
-    } else {
-      level =
-          CFX_Font::s_WeightPow_11[index] *
-          (FXSYS_abs((int)(ft_matrix.xx)) + FXSYS_abs((int)(ft_matrix.xy))) /
-          36655;
-    }
-    FXFT_Outline_Embolden(FXFT_Get_Glyph_Outline(m_Face), level);
+    pdfium::base::CheckedNumeric<signed long> level = 0;
+    if (pSubstFont->m_Charset == FXFONT_SHIFTJIS_CHARSET)
+      level = CFX_Font::s_WeightPow_SHIFTJIS[index] * 2;
+    else
+      level = CFX_Font::s_WeightPow_11[index];
+
+    level = level * (FXSYS_abs(static_cast<int>(ft_matrix.xx)) +
+                     FXSYS_abs(static_cast<int>(ft_matrix.xy))) /
+            36655;
+    FXFT_Outline_Embolden(FXFT_Get_Glyph_Outline(m_Face),
+                          level.ValueOrDefault(0));
   }
   FXFT_Library_SetLcdFilter(CFX_GEModule::Get()->GetFontMgr()->GetFTLibrary(),
                             FT_LCD_FILTER_DEFAULT);
   error = FXFT_Render_Glyph(m_Face, anti_alias);
   if (error)
     return nullptr;
   int bmwidth = FXFT_Get_Bitmap_Width(FXFT_Get_Glyph_Bitmap(m_Face));
   int bmheight = FXFT_Get_Bitmap_Rows(FXFT_Get_Glyph_Bitmap(m_Face));
   if (bmwidth > 2048 || bmheight > 2048)
     return nullptr;
@@ skipping 195 matching lines @@
     return it2->second;
 
   CFX_GlyphBitmap* pGlyphBitmap = RenderGlyph(pFont, glyph_index, bFontStyle,
                                               pMatrix, dest_width, anti_alias);
   if (!pGlyphBitmap)
     return nullptr;
 
   pSizeCache->m_GlyphMap[glyph_index] = pGlyphBitmap;
   return pGlyphBitmap;
 }