Implement 'setVariableValue' for debugger block scopes.

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/v8.h"
 
 #include "src/accessors.h"
 #include "src/arguments.h"
 #include "src/debug.h"
 #include "src/deoptimizer.h"
@@ skipping 968 matching lines @@
       Runtime::DefineObjectProperty(ext, variable_name, new_value, NONE)
           .Assert();
       return true;
     }
   }
 
   return false;
 }
 
 
+static bool SetBlockContextVariableValue(Handle<Context> block_context,
+                                         Handle<String> variable_name,
+                                         Handle<Object> new_value) {
+  DCHECK(block_context->IsBlockContext());
+  Handle<ScopeInfo> scope_info(ScopeInfo::cast(block_context->extension()));
+
+  return SetContextLocalValue(block_context->GetIsolate(), scope_info,
+                              block_context, variable_name, new_value);
+}
+
+
 // Create a plain JSObject which materializes the scope for the specified
 // catch context.
 MUST_USE_RESULT static MaybeHandle<JSObject> MaterializeCatchScope(
     Isolate* isolate, Handle<Context> context) {
   DCHECK(context->IsCatchContext());
   Handle<String> name(String::cast(context->extension()));
   Handle<Object> thrown_object(context->get(Context::THROWN_OBJECT_INDEX),
                                isolate);
   Handle<JSObject> catch_scope =
       isolate->factory()->NewJSObject(isolate->object_function());
@@ skipping 298 matching lines @@
                                      variable_name, new_value);
       case ScopeIterator::ScopeTypeWith:
         break;
       case ScopeIterator::ScopeTypeCatch:
         return SetCatchVariableValue(isolate_, CurrentContext(), variable_name,
                                      new_value);
       case ScopeIterator::ScopeTypeClosure:
         return SetClosureVariableValue(isolate_, CurrentContext(),
                                        variable_name, new_value);
       case ScopeIterator::ScopeTypeBlock:
-        // TODO(2399): should we implement it?
-        break;
+        return SetBlockContextVariableValue(CurrentContext(), variable_name,
+                                            new_value);
       case ScopeIterator::ScopeTypeModule:
         // TODO(2399): should we implement it?
         break;
     }
     return false;
   }
 
   Handle<ScopeInfo> CurrentScopeInfo() {
     DCHECK(!failed_);
     if (!nested_scope_chain_.is_empty()) {
@@ skipping 1403 matching lines @@
   return Smi::FromInt(isolate->debug()->is_active());
 }
 
 
 RUNTIME_FUNCTION(RuntimeReference_DebugBreakInOptimizedCode) {
   UNIMPLEMENTED();
   return NULL;
 }
 }
 }  // namespace v8::internal