AllocationProfiler: introduce allocation_profiler flag in V8 api.

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 2044 matching lines @@
   CHECK_EQ(0, untracked_objects);
 }
 
 
 static HeapProfilerExtension kHeapProfilerExtension;
 v8::DeclareExtension kHeapProfilerExtensionDeclaration(
     &kHeapProfilerExtension);
 
 
 // This is an example of using checking of JS allocations tracking in a test.
+TEST(AllocationProfilerString) {
+  v8::internal::Isolate::Current()->enable_allocation_profiler();
+  const char* extensions[] = { HeapProfilerExtension::kName };
+  v8::ExtensionConfiguration config(1, extensions);
+  LocalContext env(&config);
+  v8::HandleScope scope(env->GetIsolate());
+  HeapObjectsTracker tracker;
+  CompileRun("var a = new String("   ");findUntrackedObjects();");
+}
+
+
+// This is an example of using checking of JS allocations tracking in a test.
 TEST(HeapObjectsTracker) {
   const char* extensions[] = { HeapProfilerExtension::kName };
   v8::ExtensionConfiguration config(1, extensions);
   LocalContext env(&config);
   v8::HandleScope scope(env->GetIsolate());
   HeapObjectsTracker tracker;
   CompileRun("var a = 1.2");
   CompileRun("var a = 1.2; var b = 1.0; var c = 1.0;");
   CompileRun(
     "var a = [];\n"
@@ skipping 95 matching lines @@
 
   const char* names[] =
       { "(anonymous function)", "start", "f_0_0", "f_0_1", "f_0_2" };
   AllocationTraceNode* node =
       FindNode(tracker, Vector<const char*>(names, ARRAY_SIZE(names)));
   CHECK_NE(NULL, node);
   CHECK_GE(node->allocation_count(), 100);
   CHECK_GE(node->allocation_size(), 4 * node->allocation_count());
   heap_profiler->StopRecordingHeapAllocations();
 }