Remove unused code for StringConcatNode from the AST and the graph builder.

vm/flow_graph_builder.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_BUILDER_H_
 #define VM_FLOW_GRAPH_BUILDER_H_
 
 #include "vm/allocation.h"
 #include "vm/ast.h"
 #include "vm/growable_array.h"
@@ skipping 175 matching lines @@
   // Moves parent context into the context register.
   void UnchainContext();
 
   void CloseFragment() { exit_ = NULL; }
   intptr_t AllocateTempIndex() { return temp_index_++; }
   void DeallocateTempIndex(intptr_t n) {
     ASSERT(temp_index_ >= n);
     temp_index_ -= n;
   }
 
-  virtual void CompiletimeStringInterpolation(const Function& interpol_func,
-                                              const Array& literals);
-
   BindInstr* BuildObjectAllocation(ConstructorCallNode* node);
   void BuildConstructorCall(ConstructorCallNode* node, Value* alloc_value);
 
   void BuildStoreContext(const LocalVariable& variable);
   void BuildLoadContext(const LocalVariable& variable);
 
   void BuildThrowNode(ThrowNode* node);
 
   ClosureCallComp* BuildClosureCall(ClosureCallNode* node);
 
@@ skipping 56 matching lines @@
 
   // Specify a computation as the final result.  Adds a Bind instruction to
   // the graph and returns its temporary value (i.e., set the output
   // parameters).
   virtual void ReturnComputation(Computation* computation) {
     BindInstr* defn = new BindInstr(computation);
     AddInstruction(defn);
     ReturnValue(new UseVal(defn));
   }
 
-  virtual void CompiletimeStringInterpolation(const Function& interpol_func,
-                                              const Array& literals);
-
   virtual void BuildTypeTest(ComparisonNode* node);
   virtual void BuildTypeCast(ComparisonNode* node);
 };
 
 
 // Translate an AstNode to a control-flow graph fragment for both its
 // effects and true/false control flow (e.g., for an expression in a test
 // context).  The resulting graph is always closed (even if it is empty)
 // Successor control flow is explicitly set by a pair of pointers to
 // TargetEntryInstr*.
@@ skipping 39 matching lines @@
   // Output parameters.
   TargetEntryInstr** true_successor_address_;
   TargetEntryInstr** false_successor_address_;
 
   intptr_t condition_token_pos_;
 };
 
 }  // namespace dart
 
 #endif  // VM_FLOW_GRAPH_BUILDER_H_