Convert EqualityCompare to StrictCompare if reciever is either null or guaranteed to have default e…

runtime/vm/flow_graph_optimizer.h

Index: runtime/vm/flow_graph_optimizer.h
diff --git a/runtime/vm/flow_graph_optimizer.h b/runtime/vm/flow_graph_optimizer.h
index 1b48ac2c1eef2bec18721578fc6afde7ffe76ad9..80c8e7f26f1de56d39c36290c19983e158241d29 100644
--- a/runtime/vm/flow_graph_optimizer.h
+++ b/runtime/vm/flow_graph_optimizer.h
@@ -155,6 +155,12 @@ class FlowGraphOptimizer : public FlowGraphVisitor {
   void HandleEqualityCompare(EqualityCompareInstr* comp,
                              T current_instruction);
 
+  static bool CanStrictifyEqualityCompare(EqualityCompareInstr* call);
+
+  template <typename T>
+  bool StrictifyEqualityCompare(EqualityCompareInstr* compare,
+                                T current_instruction) const;
+
   void OptimizeLeftShiftBitAndSmiOp(Definition* bit_and_instr,
                                     Definition* left_instr,
                                     Definition* right_instr);