Re-enable several MSVC warnings

core/fxcrt/fx_basic_maps.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 "core/fxcrt/plex.h"
 #include "core/include/fxcrt/fx_basic.h"
 
 CFX_MapPtrToPtr::CFX_MapPtrToPtr(int nBlockSize)
@@ skipping 21 matching lines @@
   return ((FX_DWORD)(uintptr_t)key) >> 4;
 }
 void CFX_MapPtrToPtr::GetNextAssoc(FX_POSITION& rNextPosition,
                                    void*& rKey,
                                    void*& rValue) const {
   ASSERT(m_pHashTable);
   CAssoc* pAssocRet = (CAssoc*)rNextPosition;
   ASSERT(pAssocRet);
   if (pAssocRet == (CAssoc*)-1) {
     for (FX_DWORD nBucket = 0; nBucket < m_nHashTableSize; nBucket++) {
-      if ((pAssocRet = m_pHashTable[nBucket]))
+      pAssocRet = m_pHashTable[nBucket];
+      if (pAssocRet)
         break;
     }
     ASSERT(pAssocRet);
   }
-  CAssoc* pAssocNext;
-  if ((pAssocNext = pAssocRet->pNext) == NULL) {
-    for (FX_DWORD nBucket = (HashKey(pAssocRet->key) % m_nHashTableSize) + 1;
-         nBucket < m_nHashTableSize; nBucket++) {
-      if ((pAssocNext = m_pHashTable[nBucket])) {
-        break;
-      }
-    }
+  CAssoc* pAssocNext = pAssocRet->pNext;
+  for (FX_DWORD nBucket = (HashKey(pAssocRet->key) % m_nHashTableSize) + 1;
+       nBucket < m_nHashTableSize && !pAssocNext; nBucket++) {
+    pAssocNext = m_pHashTable[nBucket];
   }
   rNextPosition = (FX_POSITION)pAssocNext;
   rKey = pAssocRet->key;
   rValue = pAssocRet->value;
 }
 FX_BOOL CFX_MapPtrToPtr::Lookup(void* key, void*& rValue) const {
   FX_DWORD nHash;
   CAssoc* pAssoc = GetAssocAt(key, nHash);
   if (!pAssoc) {
     return FALSE;
@@ skipping 85 matching lines @@
 }
 void CFX_MapPtrToPtr::FreeAssoc(CFX_MapPtrToPtr::CAssoc* pAssoc) {
   pAssoc->pNext = m_pFreeList;
   m_pFreeList = pAssoc;
   m_nCount--;
   ASSERT(m_nCount >= 0);
   if (m_nCount == 0) {
     RemoveAll();
   }
 }