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/leb128_test.cc b/runtime/leb128_test.cc
index d75d5c2..5d157dc 100644
--- a/runtime/leb128_test.cc
+++ b/runtime/leb128_test.cc
@@ -253,8 +253,8 @@
 }
 
 TEST(Leb128Test, Speed) {
-  UniquePtr<Histogram<uint64_t> > enc_hist(new Histogram<uint64_t>("Leb128EncodeSpeedTest", 5));
-  UniquePtr<Histogram<uint64_t> > dec_hist(new Histogram<uint64_t>("Leb128DecodeSpeedTest", 5));
+  std::unique_ptr<Histogram<uint64_t>> enc_hist(new Histogram<uint64_t>("Leb128EncodeSpeedTest", 5));
+  std::unique_ptr<Histogram<uint64_t>> dec_hist(new Histogram<uint64_t>("Leb128DecodeSpeedTest", 5));
   Leb128EncodingVector builder;
   // Push back 1024 chunks of 1024 values measuring encoding speed.
   uint64_t last_time = NanoTime();