Expose a lower bound of malloc'd memory via heap statistics

src/compiler/graph-visualizer.cc

Index: src/compiler/graph-visualizer.cc
diff --git a/src/compiler/graph-visualizer.cc b/src/compiler/graph-visualizer.cc
index 6a9e620d0bc8d2a71a58e5a040f735d9b04d0dcb..301e3900e1c052fb61f6dd8486d1121721d631ee 100644
--- a/src/compiler/graph-visualizer.cc
+++ b/src/compiler/graph-visualizer.cc
@@ -197,7 +197,8 @@ class JSONGraphEdgeWriter {
 
 
 std::ostream& operator<<(std::ostream& os, const AsJSON& ad) {
-  Zone tmp_zone;
+  base::AccountingAllocator allocator;
+  Zone tmp_zone(&allocator);
   os << "{\n\"nodes\":[";
   JSONGraphNodeWriter(os, &tmp_zone, &ad.graph, ad.positions).Print();
   os << "],\n\"edges\":[";
@@ -583,14 +584,16 @@ void GraphC1Visualizer::PrintLiveRange(const LiveRange* range, const char* type,
 
 
 std::ostream& operator<<(std::ostream& os, const AsC1VCompilation& ac) {
-  Zone tmp_zone;
+  base::AccountingAllocator allocator;
+  Zone tmp_zone(&allocator);
   GraphC1Visualizer(os, &tmp_zone).PrintCompilation(ac.info_);
   return os;
 }
 
 
 std::ostream& operator<<(std::ostream& os, const AsC1V& ac) {
-  Zone tmp_zone;
+  base::AccountingAllocator allocator;
+  Zone tmp_zone(&allocator);
   GraphC1Visualizer(os, &tmp_zone)
       .PrintSchedule(ac.phase_, ac.schedule_, ac.positions_, ac.instructions_);
   return os;
@@ -599,7 +602,8 @@ std::ostream& operator<<(std::ostream& os, const AsC1V& ac) {
 
 std::ostream& operator<<(std::ostream& os,
                          const AsC1VRegisterAllocationData& ac) {
-  Zone tmp_zone;
+  base::AccountingAllocator allocator;
+  Zone tmp_zone(&allocator);
   GraphC1Visualizer(os, &tmp_zone).PrintLiveRanges(ac.phase_, ac.data_);
   return os;
 }
@@ -609,7 +613,8 @@ const int kOnStack = 1;
 const int kVisited = 2;
 
 std::ostream& operator<<(std::ostream& os, const AsRPO& ar) {
-  Zone local_zone;
+  base::AccountingAllocator allocator;
+  Zone local_zone(&allocator);
   ZoneVector<byte> state(ar.graph.NodeCount(), kUnvisited, &local_zone);
   ZoneStack<Node*> stack(&local_zone);