Sampling heap profiler: Fix potential crash on accessing scripts.

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 92 matching lines @@
 
   // Methods that construct v8::AllocationProfile.
 
   // Translates the provided AllocationNode *node* returning an equivalent
   // AllocationProfile::Node. The newly created AllocationProfile::Node is added
   // to the provided AllocationProfile *profile*. Line numbers, column numbers,
   // and script names are resolved using *scripts* which maps all currently
   // loaded scripts keyed by their script id.
   v8::AllocationProfile::Node* TranslateAllocationNode(
       AllocationProfile* profile, SamplingHeapProfiler::AllocationNode* node,
-      const std::map<int, Script*>& scripts);
+      const std::map<int, Handle<Script>>& scripts);
   v8::AllocationProfile::Allocation ScaleSample(size_t size,
                                                 unsigned int count);
   AllocationNode* AddStack();
   AllocationNode* FindOrAddChildNode(AllocationNode* parent, const char* name,
                                      int script_id, int start_position);
 
   Isolate* const isolate_;
   Heap* const heap_;
   base::SmartPointer<SamplingAllocationObserver> new_space_observer_;
   base::SmartPointer<SamplingAllocationObserver> other_spaces_observer_;
@@ skipping 33 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_