[presubmit] Enable readability/namespace linter checking.

test/cctest/test-ast-expression-visitor.cc

 // Copyright 2015 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 <stdlib.h>
 
 #include "src/v8.h"
 
 #include "src/ast.h"
 #include "src/ast-expression-visitor.h"
@@ skipping 27 matching lines @@
   info.set_allow_lazy_parsing(false);
   info.set_toplevel(true);
 
   CHECK(i::Compiler::ParseAndAnalyze(&info));
 
   ExpressionTypeCollector(
       isolate, handles->main_zone(),
       info.scope()->declarations()->at(0)->AsFunctionDeclaration()->fun(), dst)
       .Run();
 }
-}
+
+}  // namespace
 
 
 TEST(VisitExpressions) {
   v8::V8::Initialize();
   HandleAndZoneScope handles;
   ZoneVector<ExpressionTypeEntry> types(handles.main_zone());
   const char test_function[] =
       "function GeometricMean(stdlib, foreign, buffer) {\n"
       "  \"use asm\";\n"
       "\n"
@@ skipping 324 matching lines @@
     CHECK_EXPR(FunctionLiteral, Bounds::Unbounded()) {
       CHECK_EXPR(BinaryOperation, Bounds::Unbounded()) {
         // Skip x + x
         CHECK_SKIP();
         CHECK_EXPR(Literal, Bounds::Unbounded());
       }
     }
   }
   CHECK_TYPES_END
 }