Add Decryptor interface.

media/crypto/aes_decryptor.cc

Index: media/crypto/aes_decryptor.cc
diff --git a/media/crypto/aes_decryptor.cc b/media/crypto/aes_decryptor.cc
index 49275fb7f031db0c45b46da9d61bffbe179f493c..2a18e83e1c47e842068528224901759de3de1c9d 100644
--- a/media/crypto/aes_decryptor.cc
+++ b/media/crypto/aes_decryptor.cc
@@ -53,7 +53,7 @@ static scoped_refptr<DecoderBuffer> DecryptData(const DecoderBuffer& input,
 }
 
 AesDecryptor::AesDecryptor(DecryptorClient* client)
-    : client_(client) {
+    : Decryptor(client) {
 }
 
 AesDecryptor::~AesDecryptor() {
@@ -70,8 +70,8 @@ void AesDecryptor::GenerateKeyRequest(const std::string& key_system,
   scoped_array<uint8> message(new uint8[message_length]);
   memcpy(message.get(), init_data, message_length);
 
-  client_->KeyMessage(key_system, session_id_string,
-                      message.Pass(), message_length, "");
+  client()->KeyMessage(key_system, session_id_string,
+                       message.Pass(), message_length, "");
 }
 
 void AesDecryptor::AddKey(const std::string& key_system,
@@ -89,7 +89,7 @@ void AesDecryptor::AddKey(const std::string& key_system,
   const int kSupportedKeyLength = 16;  // 128-bit key.
   if (key_length != kSupportedKeyLength) {
     DVLOG(1) << "Invalid key length: " << key_length;
-    client_->KeyError(key_system, session_id, kUnknownError, 0);
+    client()->KeyError(key_system, session_id, Decryptor::kUnknownError, 0);
     return;
   }
 
@@ -110,7 +110,7 @@ void AesDecryptor::AddKey(const std::string& key_system,
       crypto::SymmetricKey::AES, key_string);
   if (!symmetric_key) {
     DVLOG(1) << "Could not import key.";
-    client_->KeyError(key_system, session_id, kUnknownError, 0);
+    client()->KeyError(key_system, session_id, Decryptor::kUnknownError, 0);
     return;
   }
 
@@ -124,7 +124,7 @@ void AesDecryptor::AddKey(const std::string& key_system,
     key_map_[key_id_string] = symmetric_key;
   }
 
-  client_->KeyAdded(key_system, session_id);
+  client()->KeyAdded(key_system, session_id);
 }
 
 void AesDecryptor::CancelKeyRequest(const std::string& key_system,