discardable_memory: Using mojo IPC to replace Chrome IPC

components/discardable_memory/common/BUILD.gn

 # Copyright 2016 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("//testing/test.gni")
 
 component("common") {
   output_name = "discardable_memory_common"
 
   defines = [ "DISCARDABLE_MEMORY_IMPLEMENTATION" ]
 
   sources = [
     "discardable_memory_export.h",
     "discardable_shared_memory_heap.cc",
     "discardable_shared_memory_heap.h",
-    "discardable_shared_memory_id.h",
   ]
 
   deps = [
     "//base",
   ]
 }
 
 source_set("unit_tests") {
   testonly = true
 
   sources = [
     "discardable_shared_memory_heap_unittest.cc",
   ]
 
   deps = [
     ":common",
     "//base",
     "//testing/gtest",
   ]
 }