Implement tracing interface for v8

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.
 
 # Because standalone V8 builds are not supported, assume this is part of a
 # Chromium build.
 import("//build/module_args/v8.gni")
 
 # TODO(jochen): These will need to be user-settable to support standalone V8
 # builds.
@@ skipping 932 matching lines @@
     "src/string-search.cc",
     "src/string-search.h",
     "src/string-stream.cc",
     "src/string-stream.h",
     "src/strings-storage.cc",
     "src/strings-storage.h",
     "src/strtod.cc",
     "src/strtod.h",
     "src/token.cc",
     "src/token.h",
+    "src/tracing/event-tracer.cc",
+    "src/tracing/trace-event.h",
     "src/transitions-inl.h",
     "src/transitions.cc",
     "src/transitions.h",
     "src/type-feedback-vector-inl.h",
     "src/type-feedback-vector.cc",
     "src/type-feedback-vector.h",
     "src/type-info.cc",
     "src/type-info.h",
     "src/types-inl.h",
     "src/types.cc",
@@ skipping 594 matching lines @@
       sources += [
         "src/d8-debug.cc",
         "$target_gen_dir/d8-js.cc",
       ]
     }
     if (v8_enable_i18n_support) {
       deps += [ "//third_party/icu" ]
     }
   }
 }