Sampling heap profiler: remove empty nodes from profile.

src/profiler/sampling-heap-profiler.h

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_PROFILER_SAMPLING_HEAP_PROFILER_H_
 #define V8_PROFILER_SAMPLING_HEAP_PROFILER_H_
 
 #include <deque>
 #include <map>
 #include <set>
@@ skipping 53 matching lines @@
     AllocationNode* const owner;
     Global<Value> global;
     SamplingHeapProfiler* const profiler;
 
    private:
     DISALLOW_COPY_AND_ASSIGN(Sample);
   };
 
   class AllocationNode {
    public:
-    AllocationNode(const char* const name, int script_id,
-                   const int start_position)
-        : script_id_(script_id),
+    AllocationNode(AllocationNode* parent, const char* name, int script_id,
+                   int start_position)
+        : parent_(parent),
+          script_id_(script_id),
           script_position_(start_position),
-          name_(name) {}
+          name_(name),
+          pinned_(false) {}
     ~AllocationNode() {
       for (auto child : children_) {
         delete child;
       }
     }
 
    private:
     std::map<size_t, unsigned int> allocations_;
     std::vector<AllocationNode*> children_;
+    AllocationNode* const parent_;
     const int script_id_;
     const int script_position_;
     const char* const name_;
+    bool pinned_;
 
     friend class SamplingHeapProfiler;
 
     DISALLOW_COPY_AND_ASSIGN(AllocationNode);
   };
 
  private:
   Heap* heap() const { return heap_; }
 
   void SampleObject(Address soon_object, size_t size);
@@ skipping 56 matching lines @@
   SamplingHeapProfiler* const profiler_;
   Heap* const heap_;
   base::RandomNumberGenerator* const random_;
   uint64_t const rate_;
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_PROFILER_SAMPLING_HEAP_PROFILER_H_