Add HeapProfiler::GetPersistentHandleCount to be able to track the number of persistent handles

test/cctest/test-heap-profiler.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 //
 // Tests for heap profiler
 
 #include "v8.h"
 
 #include "cctest.h"
 #include "heap-profiler.h"
 #include "snapshot.h"
 #include "utils-inl.h"
@@ skipping 1261 matching lines @@
       v8::HeapProfiler::TakeSnapshot(v8_str("fun"));
   const v8::HeapGraphNode* global = GetGlobalObject(snapshot);
   CHECK_NE(NULL, global);
   const v8::HeapGraphNode* fun =
       GetProperty(global, v8::HeapGraphEdge::kShortcut, "fun");
   CHECK(HasWeakEdge(fun));
   const v8::HeapGraphNode* shared =
       GetProperty(fun, v8::HeapGraphEdge::kInternal, "shared");
   CHECK(HasWeakEdge(shared));
 }
+

[Vyacheslav Egorov (Chromium), 2012/03/07 17:07:02]

one more empty line

+TEST(PersistentHandleCount) {
+  v8::HandleScope scope;
+  LocalContext env;
+
+  // V8 also uses global handles internally, so we can't test for an absolute
+  // number.
+  int global_handle_count = v8::HeapProfiler::GetPersistentHandleCount();
+
+  // Create some persistent handles.
+  v8::Persistent<v8::String> p_AAA =
+      v8::Persistent<v8::String>::New(v8_str("AAA"));
+  CHECK_EQ(global_handle_count + 1,
+           v8::HeapProfiler::GetPersistentHandleCount());
+  v8::Persistent<v8::String> p_BBB =
+      v8::Persistent<v8::String>::New(v8_str("BBB"));
+  CHECK_EQ(global_handle_count + 2,
+           v8::HeapProfiler::GetPersistentHandleCount());
+  v8::Persistent<v8::String> p_CCC =
+      v8::Persistent<v8::String>::New(v8_str("CCC"));
+  CHECK_EQ(global_handle_count + 3,
+           v8::HeapProfiler::GetPersistentHandleCount());
+
+  // Dipose the persistent handles in a different order.
+  p_AAA.Dispose();
+  CHECK_EQ(global_handle_count + 2,
+           v8::HeapProfiler::GetPersistentHandleCount());
+  p_CCC.Dispose();
+  CHECK_EQ(global_handle_count + 1,
+           v8::HeapProfiler::GetPersistentHandleCount());
+  p_BBB.Dispose();
+  CHECK_EQ(global_handle_count, v8::HeapProfiler::GetPersistentHandleCount());
+}