MdePkg: Add gmock examples

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4389

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: Chris Johnson <chris.n.johnson@intel.com>
Acked-by: Liming Gao <gaoliming@byosoft.com.cn>
Reviewed-by: Oliver Smith-Denny <osde@linux.microsoft.com>
Reviewed-by: Michael D Kinney <michael.d.kinney@intel.com>

MdePkg/Test/Mock/Library/GoogleTest/MockUefiLib/MockUefiLib.cpp

@@ -0,0 +1,12 @@
+/** @file
+  Google Test mocks for UefiLib
+
+  Copyright (c) 2022, Intel Corporation. All rights reserved.
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+**/
+#include <GoogleTest/Library/MockUefiLib.h>
+
+MOCK_INTERFACE_DEFINITION(MockUefiLib);
+
+MOCK_FUNCTION_DEFINITION(MockUefiLib, GetVariable2, 4, EFIAPI);
+MOCK_FUNCTION_DEFINITION(MockUefiLib, GetEfiGlobalVariable2, 3, EFIAPI);

MdePkg/Test/Mock/Library/GoogleTest/MockUefiLib/MockUefiLib.inf

@@ -0,0 +1,33 @@
+## @file
+# Google Test mocks for UefiLib
+#
+# Copyright (c) 2022, Intel Corporation. All rights reserved.
+# SPDX-License-Identifier: BSD-2-Clause-Patent
+##
+
+[Defines]
+  INF_VERSION                    = 0x00010005
+  BASE_NAME                      = MockUefiLib
+  FILE_GUID                      = 47211F7A-6D90-4DFB-BDF9-610B69197C2E
+  MODULE_TYPE                    = HOST_APPLICATION
+  VERSION_STRING                 = 1.0
+  LIBRARY_CLASS                  = UefiLib
+
+#
+# The following information is for reference only and not required by the build tools.
+#
+#  VALID_ARCHITECTURES           = IA32 X64
+#
+
+[Sources]
+  MockUefiLib.cpp
+
+[Packages]
+  MdePkg/MdePkg.dec
+  UnitTestFrameworkPkg/UnitTestFrameworkPkg.dec
+
+[LibraryClasses]
+  GoogleTestLib
+
+[BuildOptions]
+  MSFT:*_*_*_CC_FLAGS = /EHsc