Replace custom BoringSSL scopers with bssl::UniquePtr.

BoringSSL already provides C++ scopers.

Test: mma
Change-Id: I34d4ec36fc0b51750560be0886768a83fe69fbf5
diff --git a/keystore/blob.cpp b/keystore/blob.cpp
index 0987139..cea652f 100644
--- a/keystore/blob.cpp
+++ b/keystore/blob.cpp
@@ -42,16 +42,6 @@
 
 constexpr size_t kGcmIvSizeBytes = 96 / 8;
 
-template <typename T, void (*FreeFunc)(T*)> struct OpenSslObjectDeleter {
-    void operator()(T* p) { FreeFunc(p); }
-};
-
-#define DEFINE_OPENSSL_OBJECT_POINTER(name)                                                        \
-    typedef OpenSslObjectDeleter<name, name##_free> name##_Delete;                                 \
-    typedef std::unique_ptr<name, name##_Delete> name##_Ptr;
-
-DEFINE_OPENSSL_OBJECT_POINTER(EVP_CIPHER_CTX);
-
 #if defined(__clang__)
 #define OPTNONE __attribute__((optnone))
 #elif defined(__GNUC__)
@@ -92,7 +82,7 @@
     // There can be 128-bit and 256-bit keys
     const EVP_CIPHER* cipher = getAesCipherForKey(key);
 
-    EVP_CIPHER_CTX_Ptr ctx(EVP_CIPHER_CTX_new());
+    bssl::UniquePtr<EVP_CIPHER_CTX> ctx(EVP_CIPHER_CTX_new());
 
     EVP_EncryptInit_ex(ctx.get(), cipher, nullptr /* engine */, key.data(), iv);
     EVP_CIPHER_CTX_set_padding(ctx.get(), 0 /* no padding needed with GCM */);
@@ -129,7 +119,7 @@
     // There can be 128-bit and 256-bit keys
     const EVP_CIPHER* cipher = getAesCipherForKey(key);
 
-    EVP_CIPHER_CTX_Ptr ctx(EVP_CIPHER_CTX_new());
+    bssl::UniquePtr<EVP_CIPHER_CTX> ctx(EVP_CIPHER_CTX_new());
 
     EVP_DecryptInit_ex(ctx.get(), cipher, nullptr /* engine */, key.data(), iv);
     EVP_CIPHER_CTX_set_padding(ctx.get(), 0 /* no padding needed with GCM */);