Introduce object visitor to estimate the size of a native context.

BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/android/config.gni")
 import("//build/config/arm.gni")
 import("//build/config/mips.gni")
 
 # Because standalone V8 builds are not supported, assume this is part of a
 # Chromium build.
@@ skipping 804 matching lines @@
     "src/compiler/typer.cc",
     "src/compiler/typer.h",
     "src/compiler/value-numbering-reducer.cc",
     "src/compiler/value-numbering-reducer.h",
     "src/compiler/verifier.cc",
     "src/compiler/verifier.h",
     "src/compiler/zone-pool.cc",
     "src/compiler/zone-pool.h",
     "src/compiler.cc",
     "src/compiler.h",
+    "src/context-measure.cc",
+    "src/context-measure.h",
     "src/contexts.cc",
     "src/contexts.h",
     "src/conversions-inl.h",
     "src/conversions.cc",
     "src/conversions.h",
     "src/counters.cc",
     "src/counters.h",
     "src/cpu-profiler-inl.h",
     "src/cpu-profiler.cc",
     "src/cpu-profiler.h",
@@ skipping 943 matching lines @@
     if (!is_component_build) {
       sources += [
         "$target_gen_dir/d8-js.cc",
       ]
     }
     if (v8_enable_i18n_support) {
       deps += [ "//third_party/icu" ]
     }
   }
 }