Now we have a proper C++ library, use std::unique_ptr.

Also remove the Android.libcxx.mk and other bits of stlport compatibility
mechanics.

Change-Id: Icdf7188ba3c79cdf5617672c1cfd0a68ae596a61
diff --git a/runtime/dex_instruction_visitor_test.cc b/runtime/dex_instruction_visitor_test.cc
index 99ad3ed..c5e63eb 100644
--- a/runtime/dex_instruction_visitor_test.cc
+++ b/runtime/dex_instruction_visitor_test.cc
@@ -17,8 +17,8 @@
 #include "dex_instruction_visitor.h"
 
 #include <iostream>
+#include <memory>
 
-#include "UniquePtrCompat.h"
 #include "gtest/gtest.h"
 
 namespace art {
@@ -26,7 +26,7 @@
 class TestVisitor : public DexInstructionVisitor<TestVisitor> {};
 
 TEST(InstructionTest, Init) {
-  UniquePtr<TestVisitor> visitor(new TestVisitor);
+  std::unique_ptr<TestVisitor> visitor(new TestVisitor);
 }
 
 class CountVisitor : public DexInstructionVisitor<CountVisitor> {