[heap-profiler] Make ownership for samples explicit

Change-Id: Ic0e513e61e3bd1a8ac8f06a1f81c27d35a7d29af
Reviewed-on: https://chromium-review.googlesource.com/911249Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Franziska Hinkelmann <franzih@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51253}

src/profiler/sampling-heap-profiler.cc

@@ -76,11 +76,7 @@ SamplingHeapProfiler::~SamplingHeapProfiler() {
   heap_->RemoveAllocationObserversFromAllSpaces(other_spaces_observer_.get(),
                                                 new_space_observer_.get());
 
-  for (auto sample : samples_) {
-    delete sample;
-  }
-  std::set<Sample*> empty;
-  samples_.swap(empty);
+  samples_.clear();
 }
 
 
@@ -101,7 +97,7 @@ void SamplingHeapProfiler::SampleObject(Address soon_object, size_t size) {
   AllocationNode* node = AddStack();
   node->allocations_[size]++;
   Sample* sample = new Sample(size, node, loc, this);
-  samples_.insert(sample);
+  samples_.emplace(sample);
   sample->global.SetWeak(sample, OnWeakCallback, WeakCallbackType::kParameter);
 }
 
@@ -123,8 +119,14 @@ void SamplingHeapProfiler::OnWeakCallback(
       node = parent;
     }
   }
-  sample->profiler->samples_.erase(sample);
-  delete sample;
+  auto it = std::find_if(sample->profiler->samples_.begin(),
+                         sample->profiler->samples_.end(),
+                         [&sample](const std::unique_ptr<Sample>& s) {
+                           return s.get() == sample;
+                         });
+
+  sample->profiler->samples_.erase(it);
+  // sample is deleted because its unique ptr was erased from samples_.
 }
 
 SamplingHeapProfiler::AllocationNode*

src/profiler/sampling-heap-profiler.h

@@ -146,7 +146,7 @@ class SamplingHeapProfiler {
   std::unique_ptr<SamplingAllocationObserver> other_spaces_observer_;
   StringsStorage* const names_;
   AllocationNode profile_root_;
-  std::set<Sample*> samples_;
+  std::set<std::unique_ptr<Sample>> samples_;
   const int stack_depth_;
   const uint64_t rate_;
   v8::HeapProfiler::SamplingFlags flags_;