void HPhase::Begin(const char* name,
                   HGraph* graph,
                   LChunk* chunk,
                   LAllocator* allocator) {
  name_ = name;
  graph_ = graph;
  chunk_ = chunk;
  allocator_ = allocator;
  if (allocator != NULL && chunk_ == NULL) {
    chunk_ = allocator->chunk();
  }
  if (FLAG_hydrogen_stats) start_ = OS::Ticks();
  start_allocation_size_ = Zone::allocation_size_;
}
void HPhase::Begin(const char* name,
                   HGraph* graph,
                   LChunk* chunk,
                   LAllocator* allocator) {
  name_ = name;
  graph_ = graph;
  chunk_ = chunk;
  allocator_ = allocator;
  if (allocator != NULL && chunk_ == NULL) {
    chunk_ = allocator->chunk();
  }
  if (FLAG_hydrogen_stats) start_ = OS::Ticks();
  start_allocation_size_ = Zone::allocation_size_;
}