Re-enable several MSVC warnings

core/fpdfapi/fpdf_page/cpdf_page.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/fpdfapi/fpdf_page/include/cpdf_page.h"
 
 #include "core/fpdfapi/fpdf_page/include/cpdf_pageobject.h"
 #include "core/fpdfapi/fpdf_page/pageint.h"
@@ skipping 122 matching lines @@
 void CPDF_Page::GetDisplayMatrix(CFX_Matrix& matrix,
                                  int xPos,
                                  int yPos,
                                  int xSize,
                                  int ySize,
                                  int iRotate) const {
   if (m_PageWidth == 0 || m_PageHeight == 0) {
     return;
   }
   CFX_Matrix display_matrix;
-  int x0, y0, x1, y1, x2, y2;
+  int x0 = 0;
+  int y0 = 0;
+  int x1 = 0;
+  int y1 = 0;
+  int x2 = 0;
+  int y2 = 0;
   iRotate %= 4;
   switch (iRotate) {
     case 0:
       x0 = xPos;
       y0 = yPos + ySize;
       x1 = xPos;
       y1 = yPos;
       x2 = xPos + xSize;
       y2 = yPos + ySize;
       break;
@@ skipping 22 matching lines @@
       y2 = yPos;
       break;
   }
   display_matrix.Set(
       ((FX_FLOAT)(x2 - x0)) / m_PageWidth, ((FX_FLOAT)(y2 - y0)) / m_PageWidth,
       ((FX_FLOAT)(x1 - x0)) / m_PageHeight,
       ((FX_FLOAT)(y1 - y0)) / m_PageHeight, (FX_FLOAT)x0, (FX_FLOAT)y0);
   matrix = m_PageMatrix;
   matrix.Concat(display_matrix);
 }