Use emplace_back over push_back to support unique_ptr.

Change-Id: Ie05a34dced7b3d90bfd14f0514e879a6a7351691
diff --git a/src/profiling/memory/unwinding.cc b/src/profiling/memory/unwinding.cc
index acdb86c..5b77eb3 100644
--- a/src/profiling/memory/unwinding.cc
+++ b/src/profiling/memory/unwinding.cc
@@ -158,14 +158,12 @@
             strncmp(name + 5, "ashmem/", 7) != 0) {
           flags |= unwindstack::MAPS_FLAGS_DEVICE_MAP;
         }
-        maps_.push_back(
+        maps_.emplace_back(
             new unwindstack::MapInfo(nullptr, start, end, pgoff, flags, name));
       });
 }
 
 void FileDescriptorMaps::Reset() {
-  for (unwindstack::MapInfo* info : maps_)
-    delete info;
   maps_.clear();
 }