Improve CPDF_SecurityHandler code style.

Make m_pEncryptDict as constant value.

Change-Id: I4f65578e936eae5bd6afe9bfed20da3ab8e20de3
Reviewed-on: https://pdfium-review.googlesource.com/15350
Reviewed-by: dsinclair <dsinclair@chromium.org>
Commit-Queue: Art Snake <art-snake@yandex-team.ru>
diff --git a/core/fpdfapi/parser/cpdf_security_handler.cpp b/core/fpdfapi/parser/cpdf_security_handler.cpp
index 4a33de1..26202ec 100644
--- a/core/fpdfapi/parser/cpdf_security_handler.cpp
+++ b/core/fpdfapi/parser/cpdf_security_handler.cpp
@@ -26,7 +26,7 @@
     0x56, 0xff, 0xfa, 0x01, 0x08, 0x2e, 0x2e, 0x00, 0xb6, 0xd0, 0x68,
     0x3e, 0x80, 0x2f, 0x0c, 0xa9, 0xfe, 0x64, 0x53, 0x69, 0x7a};
 
-void CalcEncryptKey(CPDF_Dictionary* pEncrypt,
+void CalcEncryptKey(const CPDF_Dictionary* pEncrypt,
                     const ByteString& password,
                     uint8_t* key,
                     int keylen,
@@ -99,7 +99,7 @@
 
 CPDF_SecurityHandler::~CPDF_SecurityHandler() {}
 
-bool CPDF_SecurityHandler::OnInit(CPDF_Dictionary* pEncryptDict,
+bool CPDF_SecurityHandler::OnInit(const CPDF_Dictionary* pEncryptDict,
                                   const CPDF_Array* pIdArray,
                                   const ByteString& password) {
   m_pIdArray = pIdArray;
@@ -129,7 +129,7 @@
   return m_bOwnerUnlocked ? 0xFFFFFFFF : m_Permissions;
 }
 
-static bool LoadCryptInfo(CPDF_Dictionary* pEncryptDict,
+static bool LoadCryptInfo(const CPDF_Dictionary* pEncryptDict,
                           const ByteString& name,
                           int& cipher,
                           int& keylen) {
@@ -175,7 +175,7 @@
   return IsValidKeyLengthForCipher(cipher, keylen);
 }
 
-bool CPDF_SecurityHandler::LoadDict(CPDF_Dictionary* pEncryptDict) {
+bool CPDF_SecurityHandler::LoadDict(const CPDF_Dictionary* pEncryptDict) {
   m_pEncryptDict = pEncryptDict;
   m_Version = pEncryptDict->GetIntegerFor("V");
   m_Revision = pEncryptDict->GetIntegerFor("R");
@@ -191,7 +191,7 @@
   return LoadCryptInfo(pEncryptDict, strf_name, m_Cipher, m_KeyLen);
 }
 
-bool CPDF_SecurityHandler::LoadDict(CPDF_Dictionary* pEncryptDict,
+bool CPDF_SecurityHandler::LoadDict(const CPDF_Dictionary* pEncryptDict,
                                     uint32_t type,
                                     int& cipher,
                                     int& key_len) {
diff --git a/core/fpdfapi/parser/cpdf_security_handler.h b/core/fpdfapi/parser/cpdf_security_handler.h
index c92dc46..15be505 100644
--- a/core/fpdfapi/parser/cpdf_security_handler.h
+++ b/core/fpdfapi/parser/cpdf_security_handler.h
@@ -29,7 +29,7 @@
   CPDF_SecurityHandler();
   ~CPDF_SecurityHandler();
 
-  bool OnInit(CPDF_Dictionary* pEncryptDict,
+  bool OnInit(const CPDF_Dictionary* pEncryptDict,
               const CPDF_Array* pIdArray,
               const ByteString& password);
   uint32_t GetPermissions();
@@ -57,8 +57,8 @@
   }
 
  private:
-  bool LoadDict(CPDF_Dictionary* pEncryptDict);
-  bool LoadDict(CPDF_Dictionary* pEncryptDict,
+  bool LoadDict(const CPDF_Dictionary* pEncryptDict);
+  bool LoadDict(const CPDF_Dictionary* pEncryptDict,
                 uint32_t type,
                 int& cipher,
                 int& key_len);
@@ -94,7 +94,7 @@
 
   int m_Version;
   int m_Revision;
-  UnownedPtr<CPDF_Dictionary> m_pEncryptDict;
+  UnownedPtr<const CPDF_Dictionary> m_pEncryptDict;
   UnownedPtr<const CPDF_Array> m_pIdArray;
   uint32_t m_Permissions;
   int m_Cipher;