Return MaybeHandle from NewConsString.

test/cctest/test-heap-profiler.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 427 matching lines @@
   LocalContext env(NULL, global_template);
   v8::Handle<v8::Object> global_proxy = env->Global();
   v8::Handle<v8::Object> global = global_proxy->GetPrototype().As<v8::Object>();
   CHECK_EQ(1, global->InternalFieldCount());
 
   i::Factory* factory = CcTest::i_isolate()->factory();
   i::Handle<i::String> first =
       factory->NewStringFromAscii(i::CStrVector("0123456789"));
   i::Handle<i::String> second =
       factory->NewStringFromAscii(i::CStrVector("0123456789"));
-  i::Handle<i::String> cons_string = factory->NewConsString(first, second);
+  i::Handle<i::String> cons_string =
+      factory->NewConsString(first, second).ToHandleChecked();
 
   global->SetInternalField(0, v8::ToApiHandle<v8::String>(cons_string));
 
   v8::HeapProfiler* heap_profiler = isolate->GetHeapProfiler();
   const v8::HeapSnapshot* snapshot =
       heap_profiler->TakeHeapSnapshot(v8_str("cons_strings"));
   CHECK(ValidateSnapshot(snapshot));
   const v8::HeapGraphNode* global_node = GetGlobalObject(snapshot);
 
   const v8::HeapGraphNode* string_node =
@@ skipping 2135 matching lines @@
   map.AddRange(ToAddress(0x180), 0x80, 6U);
   map.AddRange(ToAddress(0x180), 0x80, 7U);
   CHECK_EQ(7, map.GetTraceNodeId(ToAddress(0x180)));
   CHECK_EQ(5, map.GetTraceNodeId(ToAddress(0x200)));
   CHECK_EQ(3, static_cast<int>(map.size()));
 
   map.Clear();
   CHECK_EQ(0, static_cast<int>(map.size()));
   CHECK_EQ(0, map.GetTraceNodeId(ToAddress(0x400)));
 }