MdePkg: Adds Protocol for MockRng

This patch adds a protocol for MockRng. This protocol is used to
mock the Rng protocol for testing purposes.

Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Zhiguang Liu <zhiguang.liu@intel.com>

Signed-off-by: Doug Flick [MSFT] <doug.edk2@gmail.com>
Reviewed-by: Liming Gao <gaoliming@byosoft.com.cn>

MdePkg/Test/Mock/Library/GoogleTest/Protocol/MockRng.cpp

@@ -0,0 +1,21 @@
+/** @file MockRng.cpp
+  Google Test mock for Rng Protocol
+
+  Copyright (c) Microsoft Corporation.
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+**/
+
+#include <GoogleTest/Protocol/MockRng.h>
+
+MOCK_INTERFACE_DEFINITION (MockRng);
+MOCK_FUNCTION_DEFINITION (MockRng, GetInfo, 3, EFIAPI);
+MOCK_FUNCTION_DEFINITION (MockRng, GetRng, 4, EFIAPI);
+
+EFI_RNG_PROTOCOL  RNG_PROTOCOL_INSTANCE = {
+  GetInfo, // EFI_RNG_GET_INFO
+  GetRng   // EFI_RNG_GET_RNG
+};
+
+extern "C" {
+  EFI_RNG_PROTOCOL  *gRngProtocol = &RNG_PROTOCOL_INSTANCE;
+}