[gn] Configure trace_events for v8 stand-alone

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")
 import("//build/config/sanitizers/sanitizers.gni")
 
 if (is_android) {
@@ skipping 703 matching lines @@
     ]
 
     configs = [ ":internal_config" ]
   }
 }
 
 v8_source_set("v8_base") {
   visibility = [ ":*" ]  # Only targets in this file can depend on this.
 
   sources = [
-    # TODO(fmeawad): This needs to be updated to support standalone V8 builds.
-    "../base/trace_event/common/trace_event_common.h",
+    "//base/trace_event/common/trace_event_common.h",

[Michael Achenbach, 2016/05/24 12:17:53]

// refers to the project root. Both chromium and v8 stand-alone deps trace_event
into the location: root/base/trace_event/..., where root is either src or v8.

[Nico, 2016/08/03 19:17:31]

Projects outside of src.git must not depend on base, else it becomes impossible
to change. Say we wanted to rename base/...trace_event_common.h in src. We
currently can't 'cause this file refers to it but it lives in v8.

Please find a way to do what you want to do without having v8 implicitly depend
on base.

     "include/v8-debug.h",
     "include/v8-experimental.h",
     "include/v8-platform.h",
     "include/v8-profiler.h",
     "include/v8-testing.h",
     "include/v8-util.h",
     "include/v8-version.h",
     "include/v8.h",
     "include/v8config.h",
     "src/accessors.cc",
@@ skipping 1443 matching lines @@
   sources = [
     "test/fuzzer/wasm-asmjs.cc",
   ]
 
   deps = [
     ":fuzzer_support",
   ]
 
   configs = [ ":internal_config" ]
 }