MdeModulePkg: Add VarCheckLib library

What to do:
1. Add VarCheckLib LibraryClass definitions.
2. Implement VarCheckLib library instance.
The code logic are separated from Variable driver.

Why to do: Share code.
Separate variable check service from Variable driver in MdeModulePkg.
We are going to separate generic software logic code from Variable Driver
to benefit other variable driver implementation. Auth services has been done
to be AuthVariableLib, now to cover variable check service.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Star Zeng <star.zeng@intel.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18278 6f19259b-4bc3-4df7-8a09-765794883524

MdeModulePkg/Library/VarCheckLib/VarCheckLib.inf

@@ -0,0 +1,51 @@
+## @file
+#  Provides variable check services and database management.
+#
+#  Copyright (c) 2015, Intel Corporation. All rights reserved.<BR>
+#
+#  This program and the accompanying materials
+#  are licensed and made available under the terms and conditions
+#  of the BSD License which accompanies this distribution.  The
+#  full text of the license may be found at
+#  http://opensource.org/licenses/bsd-license.php
+#
+#  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+#
+##
+
+[Defines]
+  INF_VERSION                    = 0x00010005
+  BASE_NAME                      = VarCheckLib
+  MODULE_UNI_FILE                = VarCheckLib.uni
+  FILE_GUID                      = 63E12D08-0C5D-47F8-95E4-09F89D7506C5
+  MODULE_TYPE                    = DXE_RUNTIME_DRIVER
+  VERSION_STRING                 = 1.0
+  LIBRARY_CLASS                  = VarCheckLib|DXE_RUNTIME_DRIVER DXE_SMM_DRIVER
+
+#
+# The following information is for reference only and not required by the build tools.
+#
+#  VALID_ARCHITECTURES           = IA32 X64
+#
+
+[Sources]
+  VarCheckLib.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+  MdeModulePkg/MdeModulePkg.dec
+
+[LibraryClasses]
+  BaseLib
+  BaseMemoryLib
+  DebugLib
+  MemoryAllocationLib
+
+[Guids]
+  ## SOMETIMES_CONSUMES  ## Variable:L"Boot####"
+  ## SOMETIMES_CONSUMES  ## Variable:L"Driver####"
+  ## SOMETIMES_CONSUMES  ## Variable:L"SysPrep####"
+  ## SOMETIMES_CONSUMES  ## Variable:L"Key####"
+  gEfiGlobalVariableGuid
+  gEfiHardwareErrorVariableGuid  ## SOMETIMES_CONSUMES   ## Variable:L"HwErrRec####"