Fix a bunch of -Wunused-but-set-variable warnings.

core/src/fxge/ge/fx_ge_fontmap.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 "../../../include/fxge/fx_ge.h"
 #include "../../../include/fxge/fx_freetype.h"
 #include "text_int.h"
 #define GET_TT_SHORT(w)  (FX_WORD)(((w)[0] << 8) | (w)[1])
@@ skipping 1349 matching lines @@
 {
     FXSYS_FILE* pFile = FXSYS_fopen(path, "rb");
     if (pFile == NULL) {
         return;
     }
     FXSYS_fseek(pFile, 0, FXSYS_SEEK_END);
     FX_DWORD filesize = FXSYS_ftell(pFile);
     FX_BYTE buffer[16];
     FXSYS_fseek(pFile, 0, FXSYS_SEEK_SET);
     size_t readCnt = FXSYS_fread(buffer, 12, 1, pFile);
+    if (readCnt != 12) {
+        FXSYS_fclose(pFile);
+        return;
+    }
+
     if (GET_TT_LONG(buffer) == 0x74746366) {
         FX_DWORD nFaces = GET_TT_LONG(buffer + 8);
-        FX_LPBYTE offsets = FX_Alloc(FX_BYTE, nFaces * 4);
+        if (nFaces > FX_DWORD_MAX / 4) {
+            FXSYS_fclose(pFile);
+            return;
+        }
+        FX_DWORD face_bytes = nFaces * 4;
+        FX_LPBYTE offsets = FX_Alloc(FX_BYTE, face_bytes);
         if (!offsets) {
             FXSYS_fclose(pFile);
             return;
         }
-        readCnt = FXSYS_fread(offsets, nFaces * 4, 1, pFile);
+        readCnt = FXSYS_fread(offsets, face_bytes, 1, pFile);
+        if (readCnt != face_bytes) {
+            FXSYS_fclose(pFile);
+            return;
+        }
         for (FX_DWORD i = 0; i < nFaces; i ++) {
             FX_LPBYTE p = offsets + i * 4;
             ReportFace(path, pFile, filesize, GET_TT_LONG(p));
         }
         FX_Free(offsets);
     } else {
         ReportFace(path, pFile, filesize, 0);
     }
     FXSYS_fclose(pFile);
 }
@@ skipping 126 matching lines @@
         return FALSE;
     }
     CFontFaceInfo* pFont = (CFontFaceInfo*)hFont;
     name = pFont->m_FaceName;
     return TRUE;
 }
 FX_BOOL CFX_FolderFontInfo::GetFontCharset(void* hFont, int& charset)
 {
     return FALSE;
 }