Logger does not need to invoke the garbage collector to iterate the heap.

src/log.cc

Index: src/log.cc
diff --git a/src/log.cc b/src/log.cc
index b7a5507df3f14b07e00a0d156106726dca673cb0..b1d646949ad65331eb7f4397e32778b34d91c8c2 100644
--- a/src/log.cc
+++ b/src/log.cc
@@ -1546,8 +1546,6 @@ void Logger::LogCodeObject(Object* object) {
 
 void Logger::LogCodeObjects() {
   Heap* heap = isolate_->heap();
-  heap->CollectAllGarbage(Heap::kMakeHeapIterableMask,
-                          "Logger::LogCodeObjects");
   HeapIterator iterator(heap);
   DisallowHeapAllocation no_gc;
   for (HeapObject* obj = iterator.next(); obj != NULL; obj = iterator.next()) {
@@ -1634,8 +1632,6 @@ void Logger::LogExistingFunction(Handle<SharedFunctionInfo> shared,
 
 void Logger::LogCompiledFunctions() {
   Heap* heap = isolate_->heap();
-  heap->CollectAllGarbage(Heap::kMakeHeapIterableMask,
-                          "Logger::LogCompiledFunctions");
   HandleScope scope(isolate_);
   const int compiled_funcs_count = EnumerateCompiledFunctions(heap, NULL, NULL);
   ScopedVector< Handle<SharedFunctionInfo> > sfis(compiled_funcs_count);
@@ -1654,8 +1650,6 @@ void Logger::LogCompiledFunctions() {
 
 void Logger::LogAccessorCallbacks() {
   Heap* heap = isolate_->heap();
-  heap->CollectAllGarbage(Heap::kMakeHeapIterableMask,
-                          "Logger::LogAccessorCallbacks");
   HeapIterator iterator(heap);
   DisallowHeapAllocation no_gc;
   for (HeapObject* obj = iterator.next(); obj != NULL; obj = iterator.next()) {