Allow self_size to be larger than 2GB in heap snapshots.

src/heap-snapshot-generator.h

Index: src/heap-snapshot-generator.h
diff --git a/src/heap-snapshot-generator.h b/src/heap-snapshot-generator.h
index 9ea366e6c4f6b1ee5acc63edf8675aa0eb8d758b..1cea12b3a9e4b8ef1ab5feae4fd33ddfdc6e6686 100644
--- a/src/heap-snapshot-generator.h
+++ b/src/heap-snapshot-generator.h
@@ -114,14 +114,14 @@ class HeapEntry BASE_EMBEDDED {
             Type type,
             const char* name,
             SnapshotObjectId id,
-            int self_size);
+            size_t self_size);
 
   HeapSnapshot* snapshot() { return snapshot_; }
   Type type() { return static_cast<Type>(type_); }
   const char* name() { return name_; }
   void set_name(const char* name) { name_ = name; }
   inline SnapshotObjectId id() { return id_; }
-  int self_size() { return self_size_; }
+  size_t self_size() { return self_size_; }
   INLINE(int index() const);
   int children_count() const { return children_count_; }
   INLINE(int set_children_index(int index));
@@ -146,7 +146,7 @@ class HeapEntry BASE_EMBEDDED {
   unsigned type_: 4;
   int children_count_: 28;
   int children_index_;
-  int self_size_;
+  size_t self_size_;
   SnapshotObjectId id_;
   HeapSnapshot* snapshot_;
   const char* name_;
@@ -186,7 +186,7 @@ class HeapSnapshot {
   HeapEntry* AddEntry(HeapEntry::Type type,
                       const char* name,
                       SnapshotObjectId id,
-                      int size);
+                      size_t size);
   HeapEntry* AddRootEntry();
   HeapEntry* AddGcRootsEntry();
   HeapEntry* AddGcSubrootEntry(int tag);
@@ -399,7 +399,7 @@ class V8HeapExplorer : public HeapEntriesAllocator {
   HeapEntry* AddEntry(Address address,
                       HeapEntry::Type type,
                       const char* name,
-                      int size);
+                      size_t size);
 
   const char* GetSystemEntryName(HeapObject* object);