Fix a bunch of sign mismatch warnings.

core/src/fpdfapi/fpdf_page/fpdf_page_parser.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/fpdfapi/fpdf_page.h"
 #include "../../../include/fpdfapi/fpdf_module.h"
 #include "../../../include/fpdfapi/fpdf_serial.h"
 #include "pageint.h"
@@ skipping 55 matching lines @@
     m_BBox = *pBBox;
   }
   if (pStates) {
     m_pCurStates->Copy(*pStates);
   } else {
     m_pCurStates->m_GeneralState.New();
     m_pCurStates->m_GraphState.New();
     m_pCurStates->m_TextState.New();
     m_pCurStates->m_ColorState.New();
   }
-  for (int i = 0; i < FX_ArraySize(m_Type3Data); ++i) {
+  for (size_t i = 0; i < FX_ArraySize(m_Type3Data); ++i) {
     m_Type3Data[i] = 0.0;
   }
 }
 
 CPDF_StreamContentParser::~CPDF_StreamContentParser() {
   ClearAllParams();
   for (int i = 0; i < m_StateStack.GetSize(); ++i) {
     delete (CPDF_AllStates*)m_StateStack[i];
   }
   FX_Free(m_pPathPoints);
@@ skipping 1502 matching lines @@
         buf.AppendChar((char)code);
       }
       bFirst = !bFirst;
     }
   }
   if (!bFirst) {
     buf.AppendChar((char)code);
   }
   return buf.GetByteString();
 }