Convert all symbols accessor to return read only handles so that it is not necessary to create a ne…

vm/scopes.cc

 // 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.
 
 #include "vm/scopes.h"
 
 #include "vm/ast.h"
 #include "vm/bit_vector.h"
 #include "vm/object.h"
 #include "vm/parser.h"
@@ skipping 241 matching lines @@
           desc.info.scope_id = var->owner()->context_level();
         } else {
           desc.info.kind = RawLocalVarDescriptors::kStackVar;
           desc.info.scope_id = *scope_id;
         }
         desc.info.begin_pos = var->token_pos();
         desc.info.end_pos = var->owner()->end_token_pos();
         desc.info.index = var->index();
         vars->Add(desc);
       } else if (var->name().Equals(
-            Symbols::Name(Symbols::kSavedEntryContextVar))) {
+            Symbols::Name(Symbols::kSavedEntryContextVarId))) {
         // This is the local variable in which the function saves the
         // caller's chain of closure contexts (caller's CTX register).
         VarDesc desc;
         desc.name = &var->name();
         desc.info.kind = RawLocalVarDescriptors::kContextChain;
         desc.info.scope_id = 0;
         desc.info.begin_pos = 0;
         desc.info.end_pos = 0;
         desc.info.index = var->index();
         vars->Add(desc);
@@ skipping 246 matching lines @@
 
 RawContextScope* LocalScope::CreateImplicitClosureScope(const Function& func) {
   static const intptr_t kNumCapturedVars = 1;
 
   // Create a ContextScope with space for kNumCapturedVars descriptors.
   const ContextScope& context_scope =
       ContextScope::Handle(ContextScope::New(kNumCapturedVars));
 
   // Create a descriptor for 'this' variable.
   context_scope.SetTokenIndexAt(0, func.token_pos());
-  context_scope.SetNameAt(0, Symbols::ThisHandle());
+  context_scope.SetNameAt(0, Symbols::This());
   context_scope.SetIsFinalAt(0, true);
   context_scope.SetIsConstAt(0, false);
   const AbstractType& type = AbstractType::Handle(func.ParameterTypeAt(0));
   context_scope.SetTypeAt(0, type);
   context_scope.SetContextIndexAt(0, 0);
   context_scope.SetContextLevelAt(0, 0);
   ASSERT(context_scope.num_variables() == kNumCapturedVars);  // Verify count.
   return context_scope.raw();
 }
 
@@ skipping 24 matching lines @@
   } else {
     // Shift negative indexes so that the lowest one is 0 (they are still
     // non-positive).
     return fixed_parameter_count -
         (index() - ParsedFunction::kFirstLocalSlotIndex);
   }
 }
 
 
 }  // namespace dart