Clean up XFA code which causes warnings

xfa/fde/css/fde_cssstylesheet.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 "xfa/fde/css/fde_cssstylesheet.h"
 
 #include <memory>
 
@@ skipping 303 matching lines @@
         if (pFontFaceRule == NULL) {
           pFontFaceRule = FXTARGET_NewWith(m_pAllocator) CFDE_CSSFontFaceRule;
           ruleArray.Add(pFontFaceRule);
         }
         break;
       case FDE_CSSSYNTAXSTATUS_DeclClose:
         return FDE_CSSSYNTAXSTATUS_None;
         FDE_CSSSWITCHDEFAULTS();
     }
   }
-  return FDE_CSSSYNTAXSTATUS_None;
 }
 FDE_CSSSYNTAXSTATUS CFDE_CSSStyleSheet::LoadImportRule(
     CFDE_CSSSyntaxParser* pSyntax) {
   for (;;) {
     switch (pSyntax->DoSyntaxParse()) {
       case FDE_CSSSYNTAXSTATUS_ImportClose:
         return FDE_CSSSYNTAXSTATUS_None;
       case FDE_CSSSYNTAXSTATUS_URI:
         break;
         FDE_CSSSWITCHDEFAULTS();
@@ skipping 11 matching lines @@
       case FDE_CSSSYNTAXSTATUS_Selector:
       case FDE_CSSSYNTAXSTATUS_DeclOpen:
       case FDE_CSSSYNTAXSTATUS_PropertyName:
       case FDE_CSSSYNTAXSTATUS_PropertyValue:
         break;
       case FDE_CSSSYNTAXSTATUS_DeclClose:
         return FDE_CSSSYNTAXSTATUS_None;
         FDE_CSSSWITCHDEFAULTS();
     }
   }
-  return FDE_CSSSYNTAXSTATUS_None;
 }
 void CFDE_CSSStyleRule::SetSelector(IFX_MemoryAllocator* pStaticStore,
                                     const CFDE_CSSSelectorArray& list) {
   ASSERT(m_ppSelector == NULL);
   m_iSelectors = list.GetSize();
   m_ppSelector = static_cast<CFDE_CSSSelector**>(
       pStaticStore->Alloc(m_iSelectors * sizeof(CFDE_CSSSelector*)));
   for (int32_t i = 0; i < m_iSelectors; ++i) {
     m_ppSelector[i] = list.GetAt(i);
   }
@@ skipping 129 matching lines @@
       return NULL;
     }
   }
   if (pPersudoFirst == NULL) {
     return pFirst;
   } else {
     pPersudoLast->SetNext(pFirst);
     return pPersudoFirst;
   }
 }