MemRegion can refer to ASTContext without external help.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@110784 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Checker/MemRegion.cpp b/lib/Checker/MemRegion.cpp
index 5800670..3f706e1 100644
--- a/lib/Checker/MemRegion.cpp
+++ b/lib/Checker/MemRegion.cpp
@@ -178,7 +178,7 @@
 
 DefinedOrUnknownSVal DeclRegion::getExtent(ValueManager& ValMgr) const {
   ASTContext& Ctx = ValMgr.getContext();
-  QualType T = getDesugaredValueType(Ctx);
+  QualType T = getDesugaredValueType();
 
   if (isa<VariableArrayType>(T))
     return nonloc::SymbolVal(ValMgr.getSymbolManager().getExtentSymbol(this));
@@ -196,8 +196,7 @@
   // A zero-length array at the end of a struct often stands for dynamically-
   // allocated extra memory.
   if (Extent.isZeroConstant()) {
-    ASTContext& Ctx = ValMgr.getContext();
-    QualType T = getDesugaredValueType(Ctx);
+    QualType T = getDesugaredValueType();
 
     if (isa<ConstantArrayType>(T))
       return UnknownVal();
@@ -846,7 +845,7 @@
       goto Finish;
     case ElementRegionKind: {
       const ElementRegion *ER = cast<ElementRegion>(R);
-      QualType EleTy = ER->getValueType(getContext());
+      QualType EleTy = ER->getValueType();
 
       if (!IsCompleteType(getContext(), EleTy))
         return RegionOffset(0);