Expose a lower bound of malloc'd memory via heap statistics

tools/parser-shell.cc

 // Copyright 2014 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 84 matching lines @@
       break;
     }
   }
   v8::base::TimeDelta parse_time1, parse_time2;
   Handle<Script> script =
       reinterpret_cast<i::Isolate*>(isolate)->factory()->NewScript(
           v8::Utils::OpenHandle(*source_handle));
   i::ScriptData* cached_data_impl = NULL;
   // First round of parsing (produce data to cache).
   {
-    Zone zone;
+    Zone zone(reinterpret_cast<i::Isolate*>(isolate)->allocator());
     ParseInfo info(&zone, script);
     info.set_global();
     info.set_cached_data(&cached_data_impl);
     info.set_compile_options(v8::ScriptCompiler::kProduceParserCache);
     v8::base::ElapsedTimer timer;
     timer.Start();
     // Allow lazy parsing; otherwise we won't produce cached data.
     info.set_allow_lazy_parsing();
     bool success = Parser::ParseStatic(&info);
     parse_time1 = timer.Elapsed();
     if (!success) {
       fprintf(stderr, "Parsing failed\n");
       return std::make_pair(v8::base::TimeDelta(), v8::base::TimeDelta());
     }
   }
   // Second round of parsing (consume cached data).
   {
-    Zone zone;
+    Zone zone(reinterpret_cast<i::Isolate*>(isolate)->allocator());
     ParseInfo info(&zone, script);
     info.set_global();
     info.set_cached_data(&cached_data_impl);
     info.set_compile_options(v8::ScriptCompiler::kConsumeParserCache);
     v8::base::ElapsedTimer timer;
     timer.Start();
     // Allow lazy parsing; otherwise cached data won't help.
     info.set_allow_lazy_parsing();
     bool success = Parser::ParseStatic(&info);
     parse_time2 = timer.Elapsed();
@@ skipping 60 matching lines @@
              first_parse_total);
       printf("%s(SecondParseRunTime): %.f ms\n", benchmark.c_str(),
              second_parse_total);
     }
   }
   v8::V8::Dispose();
   v8::V8::ShutdownPlatform();
   delete platform;
   return 0;
 }