MdePkg: Add Google Mock Protocol for SmmCommunication (#1266)

## Description

Added MockSmmCommunication to be used by Googletests

- [ ] Impacts functionality?
- [ ] Impacts security?
- [ ] Breaking change?
- [ ] Includes tests?
- [ ] Includes documentation?
- [x] Backport to release branch?

## How This Was Tested

Added MockSmmCommunication to GoogleTests and able to successfully
include its functions

## Integration Instructions

N/A

---------

Co-authored-by: Aaron <[email protected]>

MdePkg/Test/Mock/Include/GoogleTest/Protocol/MockSmmCommunication.h

@@ -0,0 +1,42 @@
+/** @file MockSmmCommunication.h
+  Declare mock SMM Communication Protocol.
+
+  Copyright (c) Microsoft Corporation.
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+**/
+
+#ifndef MOCK_SMM_COMMUNICATION_H_
+#define MOCK_SMM_COMMUNICATION_H_
+
+#include <Library/GoogleTestLib.h>
+#include <Library/FunctionMockLib.h>
+extern "C" {
+  #include <Uefi.h>
+  #include <Pi/PiMultiPhase.h>
+  #include <Protocol/SmmCommunication.h>
+}
+
+struct MockSmmCommunicationProtocol {
+  MOCK_INTERFACE_DECLARATION (MockSmmCommunicationProtocol);
+
+  MOCK_FUNCTION_DECLARATION (
+    EFI_STATUS,
+    Communicate,
+    (
+     IN CONST EFI_MM_COMMUNICATION_PROTOCOL   *This,
+     IN OUT VOID                              *CommBuffer,
+     IN OUT UINTN                             *CommSize OPTIONAL
+    )
+    );
+};
+
+MOCK_INTERFACE_DEFINITION (MockSmmCommunicationProtocol);
+MOCK_FUNCTION_DEFINITION (MockSmmCommunicationProtocol, Communicate, 3, EFIAPI);
+
+#define MOCK_SMM_COMMUNICATION_PROTOCOL_INSTANCE(NAME)  \
+  EFI_SMM_COMMUNICATION_PROTOCOL  NAME##_INSTANCE = {   \
+    Communicate                                         \
+  };                                                    \
+  EFI_SMM_COMMUNICATION_PROTOCOL  *NAME = &NAME##_INSTANCE;
+
+#endif