Update from https://crrev.com/320343

base/memory/BUILD.gn

Index: base/memory/BUILD.gn
diff --git a/base/memory/BUILD.gn b/base/memory/BUILD.gn
new file mode 100644
index 0000000000000000000000000000000000000000..5d016ff681221bf14b12fab41c903b1ae8658a7a
--- /dev/null
+++ b/base/memory/BUILD.gn
@@ -0,0 +1,64 @@
+# Copyright (c) 2015 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.
+
+source_set("memory") {
+  sources = [
+    "aligned_memory.cc",
+    "aligned_memory.h",
+    "discardable_memory.cc",
+    "discardable_memory.h",
+    "discardable_memory_android.cc",
+    "discardable_memory_linux.cc",
+    "discardable_memory_mac.cc",
+    "discardable_memory_shmem.cc",
+    "discardable_memory_shmem.h",
+    "discardable_memory_shmem_allocator.cc",
+    "discardable_memory_shmem_allocator.h",
+    "discardable_memory_win.cc",
+    "discardable_shared_memory.cc",
+    "discardable_shared_memory.h",
+    "linked_ptr.h",
+    "manual_constructor.h",
+    "memory_pressure_listener.cc",
+    "memory_pressure_listener.h",
+    "raw_scoped_refptr_mismatch_checker.h",
+    "ref_counted.cc",
+    "ref_counted.h",
+    "ref_counted_delete_on_message_loop.h",
+    "ref_counted_memory.cc",
+    "ref_counted_memory.h",
+    "scoped_policy.h",
+    "scoped_ptr.h",
+    "scoped_vector.h",
+    "shared_memory.h",
+    "shared_memory_android.cc",
+    "shared_memory_nacl.cc",
+    "shared_memory_posix.cc",
+    "shared_memory_win.cc",
+    "singleton.cc",
+    "singleton.h",
+    "weak_ptr.cc",
+    "weak_ptr.h",
+  ]
+
+  if (is_nacl) {
+    sources -= [
+      "discardable_memory.cc",
+      "discardable_memory.h",
+      "discardable_memory_shmem.cc",
+      "discardable_memory_shmem.h",
+      "discardable_memory_shmem_allocator.cc",
+      "discardable_memory_shmem_allocator.h",
+      "discardable_shared_memory.cc",
+      "discardable_shared_memory.h",
+      "shared_memory_posix.cc",
+    ]
+  } else {
+    sources -= [ "shared_memory_nacl.cc" ]
+  }
+
+  defines = [ "BASE_IMPLEMENTATION" ]
+
+  visibility = [ "//base/*" ]
+}