Fix crash in CFDE_CSSSyntaxParser when parsing empty url

xfa/fde/css/fde_cssdeclaration.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_cssdeclaration.h"
 
 #include "core/fxcrt/fx_ext.h"
 
@@ skipping 283 matching lines @@
 }
 IFDE_CSSValue* CFDE_CSSDeclaration::ParseColor(const FDE_CSSPROPERTYARGS* pArgs,
                                                const FX_WCHAR* pszValue,
                                                int32_t iValueLen) {
   FX_ARGB dwColor;
   if (!FDE_ParseCSSColor(pszValue, iValueLen, dwColor)) {
     return nullptr;
   }
   return FXTARGET_NewWith(pArgs->pStaticStore) CFDE_CSSPrimitiveValue(dwColor);
 }
+
 IFDE_CSSValue* CFDE_CSSDeclaration::ParseURI(const FDE_CSSPROPERTYARGS* pArgs,
                                              const FX_WCHAR* pszValue,
                                              int32_t iValueLen) {
   int32_t iOffset;
-  if (!FDE_ParseCSSURI(pszValue, iValueLen, iOffset, iValueLen)) {
+  if (!FDE_ParseCSSURI(pszValue, &iOffset, &iValueLen))
     return nullptr;
-  }
-  if (iValueLen <= 0) {
+
+  if (iValueLen <= 0)
     return nullptr;
-  }
+
   pszValue = CopyToLocal(pArgs, pszValue + iOffset, iValueLen);
   return pszValue
              ? FXTARGET_NewWith(pArgs->pStaticStore)
                    CFDE_CSSPrimitiveValue(FDE_CSSPRIMITIVETYPE_URI, pszValue)
              : nullptr;
 }
+
 IFDE_CSSValue* CFDE_CSSDeclaration::ParseString(
     const FDE_CSSPROPERTYARGS* pArgs,
     const FX_WCHAR* pszValue,
     int32_t iValueLen) {
   int32_t iOffset;
-  if (!FDE_ParseCSSString(pszValue, iValueLen, iOffset, iValueLen)) {
+  if (!FDE_ParseCSSString(pszValue, iValueLen, &iOffset, &iValueLen))
     return nullptr;
-  }
-  if (iValueLen <= 0) {
+
+  if (iValueLen <= 0)
     return nullptr;
-  }
+
   pszValue = CopyToLocal(pArgs, pszValue + iOffset, iValueLen);
   return pszValue
              ? FXTARGET_NewWith(pArgs->pStaticStore)
                    CFDE_CSSPrimitiveValue(FDE_CSSPRIMITIVETYPE_String, pszValue)
              : nullptr;
 }
 IFDE_CSSValue* CFDE_CSSDeclaration::ParseFunction(
     const FDE_CSSPROPERTYARGS* pArgs,
     const FX_WCHAR* pszValue,
     int32_t iValueLen) {
@@ skipping 990 matching lines @@
 
   if (!pOverflowY)
     pOverflowY = NewEnumValue(pStaticStore, pOverflowX->GetEnum());
 
   AddPropertyHolder(pStaticStore, FDE_CSSPROPERTY_OverflowX, pOverflowX,
                     bImportant);
   AddPropertyHolder(pStaticStore, FDE_CSSPROPERTY_OverflowY, pOverflowY,
                     bImportant);
   return true;
 }