[Clang] Migrate llvm::make_unique to std::make_unique

Now that we've moved to C++14, we no longer need the llvm::make_unique
implementation from STLExtras.h. This patch is a mechanical replacement
of (hopefully) all the llvm::make_unique instances across the monorepo.

Differential revision: https://reviews.llvm.org/D66259

llvm-svn: 368942
diff --git a/clang/lib/AST/CXXInheritance.cpp b/clang/lib/AST/CXXInheritance.cpp
index ecf451b..a3a3794 100644
--- a/clang/lib/AST/CXXInheritance.cpp
+++ b/clang/lib/AST/CXXInheritance.cpp
@@ -44,7 +44,7 @@
     Decls.insert(Path->Decls.front());
 
   NumDeclsFound = Decls.size();
-  DeclsFound = llvm::make_unique<NamedDecl *[]>(NumDeclsFound);
+  DeclsFound = std::make_unique<NamedDecl *[]>(NumDeclsFound);
   std::copy(Decls.begin(), Decls.end(), DeclsFound.get());
 }