Simplify the desugaring of catch clauses.

runtime/vm/ast.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_AST_H_
 #define VM_AST_H_
 
 #include "platform/assert.h"
 #include "vm/allocation.h"
 #include "vm/growable_array.h"
@@ skipping 1654 matching lines @@
   const bool needs_stacktrace_;
 
   DISALLOW_COPY_AND_ASSIGN(CatchClauseNode);
 };
 
 
 class TryCatchNode : public AstNode {
  public:
   TryCatchNode(intptr_t token_pos,
                SequenceNode* try_block,
-               SourceLabel* end_catch_label,
                const LocalVariable* context_var,
                CatchClauseNode* catch_block,
                SequenceNode* finally_block,
                intptr_t try_index)
       : AstNode(token_pos),
         try_block_(try_block),
-        end_catch_label_(end_catch_label),
         context_var_(*context_var),
         catch_block_(catch_block),
         finally_block_(finally_block),
         try_index_(try_index) {
     ASSERT(try_block_ != NULL);
     ASSERT(context_var != NULL);
     ASSERT(catch_block_ != NULL || finally_block_ != NULL);
-    ASSERT(end_catch_label_ != NULL);
   }
 
   SequenceNode* try_block() const { return try_block_; }
-  SourceLabel* end_catch_label() const { return end_catch_label_; }
   CatchClauseNode* catch_block() const { return catch_block_; }
   SequenceNode* finally_block() const { return finally_block_; }
   const LocalVariable& context_var() const { return context_var_; }
   intptr_t try_index() const { return try_index_; }
 
   virtual void VisitChildren(AstNodeVisitor* visitor) const {
     try_block_->Visit(visitor);
     if (catch_block_ != NULL) {
       catch_block_->Visit(visitor);
     }
     if (finally_block_ != NULL) {
       finally_block_->Visit(visitor);
     }
   }
 
   DECLARE_COMMON_NODE_FUNCTIONS(TryCatchNode);
 
  private:
   SequenceNode* try_block_;
-  SourceLabel* end_catch_label_;
   const LocalVariable& context_var_;
   CatchClauseNode* catch_block_;
   SequenceNode* finally_block_;
   const intptr_t try_index_;
 
   DISALLOW_COPY_AND_ASSIGN(TryCatchNode);
 };
 
 
 class ThrowNode : public AstNode {
@@ skipping 53 matching lines @@
   const intptr_t try_index_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(InlinedFinallyNode);
 };
 
 }  // namespace dart
 
 #undef DECLARE_COMMON_NODE_FUNCTIONS
 
 #endif  // VM_AST_H_