Do not look for the slot in the ScopeInfo's global range when it's not necessary.

src/runtime/runtime-debug.cc

 // Copyright 2014 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/runtime/runtime-utils.h"
 
 #include "src/arguments.h"
 #include "src/debug/debug.h"
 #include "src/debug/debug-evaluate.h"
 #include "src/debug/debug-frames.h"
@@ skipping 550 matching lines @@
     local++;
   }
   if (local < local_count) {
     // Get the context containing declarations.
     Handle<Context> context(
         Context::cast(frame_inspector.GetContext())->declaration_context());
     for (; i < scope_info->LocalCount(); ++i) {
       if (scope_info->LocalIsSynthetic(i)) continue;
       Handle<String> name(scope_info->LocalName(i));
       VariableMode mode;
-      VariableLocation location;
       InitializationFlag init_flag;
       MaybeAssignedFlag maybe_assigned_flag;
       locals->set(local * 2, *name);
       int context_slot_index = ScopeInfo::ContextSlotIndex(
-          scope_info, name, &mode, &location, &init_flag, &maybe_assigned_flag);
-      DCHECK(VariableLocation::CONTEXT == location);
+          scope_info, name, &mode, &init_flag, &maybe_assigned_flag);
       Object* value = context->get(context_slot_index);
       locals->set(local * 2 + 1, value);
       local++;
     }
   }
 
   // Check whether this frame is positioned at return. If not top
   // frame or if the frame is optimized it cannot be at a return.
   bool at_return = false;
   if (!is_optimized && index == 0) {
@@ skipping 1133 matching lines @@
   return *isolate->factory()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(Runtime_DebugBreakInOptimizedCode) {
   UNIMPLEMENTED();
   return NULL;
 }
 }  // namespace internal
 }  // namespace v8