[debugger] fix debug-evaluate wrt shadowed context var.

src/ast/scopes.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/ast/scopes.h"
 
 #include "src/accessors.h"
 #include "src/ast/scopeinfo.h"
 #include "src/bootstrapper.h"
 #include "src/messages.h"
@@ skipping 824 matching lines @@
     int end_pos = scope->end_position();
     DCHECK(beg_pos >= 0 && end_pos >= 0);
     if (beg_pos <= position && position < end_pos) {
       scope->GetNestedScopeChain(isolate, chain, position);
       return;
     }
   }
 }
 
 
+void Scope::CollectNonLocals(HashMap* non_locals) {
+  // Collect non-local variables referenced in the scope.
+  // TODO(yangguo): store non-local variables explicitly if we can no longer
+  //                rely on unresolved_ to find them.
+  for (int i = 0; i < unresolved_.length(); i++) {
+    VariableProxy* proxy = unresolved_[i];
+    if (proxy->is_resolved() && proxy->var()->IsStackAllocated()) continue;
+    Handle<String> name = proxy->name();
+    void* key = reinterpret_cast<void*>(name.location());
+    HashMap::Entry* entry = non_locals->LookupOrInsert(key, name->Hash());
+    entry->value = key;
+  }
+  for (int i = 0; i < inner_scopes_.length(); i++) {
+    inner_scopes_[i]->CollectNonLocals(non_locals);
+  }
+}
+
+
 void Scope::ReportMessage(int start_position, int end_position,
                           MessageTemplate::Template message,
                           const AstRawString* arg) {
   // Propagate the error to the topmost scope targeted by this scope analysis
   // phase.
   Scope* top = this;
   while (!top->is_script_scope() && !top->outer_scope()->already_resolved()) {
     top = top->outer_scope();
   }
 
@@ skipping 801 matching lines @@
       function_ != NULL && function_->proxy()->var()->IsContextSlot();
   return num_heap_slots() - Context::MIN_CONTEXT_SLOTS - num_global_slots() -
          (is_function_var_in_context ? 1 : 0);
 }
 
 
 int Scope::ContextGlobalCount() const { return num_global_slots(); }
 
 }  // namespace internal
 }  // namespace v8