Use std::make_shared in LLDB (NFC)

Unlike std::make_unique, which is only available since C++14,
std::make_shared is available since C++11. Not only is std::make_shared
a lot more readable compared to ::reset(new), it also performs a single
heap allocation for the object and control block.

Differential revision: https://reviews.llvm.org/D57990

llvm-svn: 353764

lldb/source/Plugins/InstrumentationRuntime/MainThreadChecker/MainThreadCheckerRuntime.cpp

@@ -24,6 +24,8 @@
 #include "lldb/Utility/RegularExpression.h"
 #include "Plugins/Process/Utility/HistoryThread.h"
 
+#include <memory>
+
 using namespace lldb;
 using namespace lldb_private;
 
@@ -238,7 +240,7 @@ lldb::ThreadCollectionSP
 MainThreadCheckerRuntime::GetBacktracesFromExtendedStopInfo(
     StructuredData::ObjectSP info) {
   ThreadCollectionSP threads;
-  threads.reset(new ThreadCollection());
+  threads = std::make_shared<ThreadCollection>();
   
   ProcessSP process_sp = GetProcessSP();