MdeModulePkg PlatformVarCleanupLib: Locate VarCheck protocol when using

Do not locate VarCheck protocol in Constructor, then the
gEdkiiVarCheckProtocolGuid could be removed from [Depex].
It will be more flexible for the library Consumer to work without VarCheck
protocol installed, for example at recovery boot mode with EmuRuntimeDxe.

The unused UefiLib is also been removed from [LibraryClasses] in *.inf.

Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Feng Tian <feng.tian@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Star Zeng <star.zeng@intel.com>
Reviewed-by: Ruiyu Ni <ruiyu.ni@intel.com>

MdeModulePkg/Library/PlatformVarCleanupLib/PlatVarCleanupLib.c

@@ -1,7 +1,7 @@
 /** @file
   Sample platform variable cleanup library implementation.
 
-Copyright (c) 2015, Intel Corporation. All rights reserved.<BR>
+Copyright (c) 2015 - 2016, 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
@@ -100,6 +100,15 @@ IsUserVariable (
   EFI_STATUS                    Status;
   VAR_CHECK_VARIABLE_PROPERTY   Property;
 
+  if (mVarCheck == NULL) {
+    gBS->LocateProtocol (
+           &gEdkiiVarCheckProtocolGuid,
+           NULL,
+           (VOID **) &mVarCheck
+           );
+  }
+  ASSERT (mVarCheck != NULL);
+
   ZeroMem (&Property, sizeof (Property));
   Status = mVarCheck->VariablePropertyGet (
                         Name,
@@ -1225,13 +1234,6 @@ PlatformVarCleanupLibConstructor (
   mLastVarErrorFlag = InternalGetVarErrorFlag ();
   DEBUG ((EFI_D_INFO, "mLastVarErrorFlag - 0x%02x\n", mLastVarErrorFlag));
 
-  Status = gBS->LocateProtocol (
-                  &gEdkiiVarCheckProtocolGuid,
-                  NULL,
-                  (VOID **) &mVarCheck
-                  );
-  ASSERT_EFI_ERROR (Status);
-
   //
   // Register EFI_END_OF_DXE_EVENT_GROUP_GUID event.
   //

MdeModulePkg/Library/PlatformVarCleanupLib/PlatformVarCleanupLib.inf

@@ -1,7 +1,7 @@
 ## @file
 #  Sample platform variable cleanup library instance.
 #
-#  Copyright (c) 2015, Intel Corporation. All rights reserved.<BR>
+#  Copyright (c) 2015 - 2016, Intel Corporation. All rights reserved.<BR>
 #
 #  This program and the accompanying materials
 #  are licensed and made available under the terms and conditions
@@ -44,7 +44,6 @@
 [LibraryClasses]
   UefiBootServicesTableLib
   UefiRuntimeServicesTableLib
-  UefiLib
   BaseLib
   DebugLib
   BaseMemoryLib
@@ -68,6 +67,5 @@
   gEfiHiiConfigRoutingProtocolGuid  ## SOMETIMES_CONSUMES
 
 [Depex]
-  gEdkiiVarCheckProtocolGuid AND
   gEfiVariableArchProtocolGuid