Be less aggressive in sharing contexts between scopes so that sibling contexts

runtime/vm/scopes.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_SCOPES_H_
 #define VM_SCOPES_H_
 
 #include "platform/assert.h"
 #include "platform/globals.h"
 #include "vm/allocation.h"
@@ skipping 300 matching lines @@
   // and in its children scopes of the same function level. Allocating means
   // assigning a frame slot index or a context slot index.
   // Parameters to be allocated in the frame must all appear in the top scope
   // and not in its children (we do not yet handle register parameters).
   // Locals must be listed after parameters in top scope and in its children.
   // Two locals in different sibling scopes may share the same frame slot.
   // Return the index of the next available frame slot.
   int AllocateVariables(int first_parameter_index,
                         int num_parameters,
                         int first_frame_index,
-                        LocalScope* loop_owner,
-                        LocalScope** context_owner,
+                        LocalScope* context_owner,
                         bool* found_captured_variables);
 
   // Creates variable info for the scope and all its nested scopes.
   // Must be called after AllocateVariables() has been called.
   RawLocalVarDescriptors* GetVarDescriptors(const Function& func);
 
   // Create a ContextScope object describing all captured variables referenced
   // from this scope and belonging to outer scopes.
   RawContextScope* PreserveOuterScope(int current_context_level) const;
 
@@ skipping 46 matching lines @@
   // List of names referenced in this scope and its children that
   // are not resolved to local variables.
   GrowableArray<NameReference*> referenced_;
 
   DISALLOW_COPY_AND_ASSIGN(LocalScope);
 };
 
 }  // namespace dart
 
 #endif  // VM_SCOPES_H_