Add flags and skeleton for profiling process.

chrome/profiling/BUILD.gn

+# Copyright 2017 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("//chrome/common/features.gni")
+
+if (enable_oop_heap_profiling) {
+  static_library("profiling") {
+    sources = [
+      "profiling_main.cc",
+      "profiling_main.h",
+    ]
+
+    deps = [
+      "//base",
+      "//chrome/common",
+    ]
+  }
+} else {
+  # Dummy target so this can be unconditionally depended on and header checking
+  # will work.
+  source_set("profiling") {
+    sources = [
+      "profiling_main.h",
+    ]
+  }
+}