[ObjC] Remove default parameter no caller was providing. NFC intended.

Currently there is no need to make ObjCTypeParamType have a canonical type
different from the one in corresponding ObjCTypeParamDecl. So remove the
corresponding unused API.

llvm-svn: 374596
diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index 8dd57f2..cd6ea7f 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -4714,8 +4714,7 @@
 
 QualType
 ASTContext::getObjCTypeParamType(const ObjCTypeParamDecl *Decl,
-                           ArrayRef<ObjCProtocolDecl *> protocols,
-                           QualType Canonical) const {
+                                 ArrayRef<ObjCProtocolDecl *> protocols) const {
   // Look in the folding set for an existing type.
   llvm::FoldingSetNodeID ID;
   ObjCTypeParamType::Profile(ID, Decl, protocols);
@@ -4724,16 +4723,14 @@
       ObjCTypeParamTypes.FindNodeOrInsertPos(ID, InsertPos))
     return QualType(TypeParam, 0);
 
-  if (Canonical.isNull()) {
-    // We canonicalize to the underlying type.
-    Canonical = getCanonicalType(Decl->getUnderlyingType());
-    if (!protocols.empty()) {
-      // Apply the protocol qualifers.
-      bool hasError;
-      Canonical = getCanonicalType(applyObjCProtocolQualifiers(
-          Canonical, protocols, hasError, true /*allowOnPointerType*/));
-      assert(!hasError && "Error when apply protocol qualifier to bound type");
-    }
+  // We canonicalize to the underlying type.
+  QualType Canonical = getCanonicalType(Decl->getUnderlyingType());
+  if (!protocols.empty()) {
+    // Apply the protocol qualifers.
+    bool hasError;
+    Canonical = getCanonicalType(applyObjCProtocolQualifiers(
+        Canonical, protocols, hasError, true /*allowOnPointerType*/));
+    assert(!hasError && "Error when apply protocol qualifier to bound type");
   }
 
   unsigned size = sizeof(ObjCTypeParamType);