Fix super ==: Test first for null before call inf super ==.

runtime/vm/flow_graph_compiler_ia32.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_FLOW_GRAPH_COMPILER_IA32_H_
 #define VM_FLOW_GRAPH_COMPILER_IA32_H_
 
 #ifndef VM_FLOW_GRAPH_COMPILER_H_
 #error Include flow_graph_compiler.h instead of flow_graph_compiler_ia32.h.
 #endif
@@ skipping 139 matching lines @@
   void EmitDoubleCompareBranch(Condition true_condition,
                                XmmRegister left,
                                XmmRegister right,
                                BranchInstr* branch);
   void EmitDoubleCompareBool(Condition true_condition,
                              XmmRegister left,
                              XmmRegister right,
                              Register result);
 
   void EmitEqualityRegConstCompare(Register reg, const Object& obj);
+  // Implement equality: if any of the arguments is null do identity check.
+  // Fallthrough calls super equality.
+  void EmitSuperEqualityCallPrologue(Register result, Label* skip_call);
 
   intptr_t StackSize() const;
 
   // Returns assembler label associated with the given block entry.
   Label* GetBlockLabel(BlockEntryInstr* block_entry) const;
 
   // Returns true if there is a next block after the current one in
   // the block order and if it is the given block.
   bool IsNextBlock(BlockEntryInstr* block_entry) const;
 
@@ skipping 156 matching lines @@
   // that should be used when deoptimizing we store it in this variable.
   // In future AddDeoptStub should be moved out of the instruction template.
   Environment* pending_deoptimization_env_;
 
   DISALLOW_COPY_AND_ASSIGN(FlowGraphCompiler);
 };
 
 }  // namespace dart
 
 #endif  // VM_FLOW_GRAPH_COMPILER_IA32_H_