Move discardable memory to //components from //content

components/discardable_memory/client/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("client") {
+  output_name = "discardable_memory_client"
+
+  defines = [ "DISCARDABLE_MEMORY_IMPLEMENTATION" ]
+
+  sources = [
+    "child_discardable_shared_memory_manager.cc",
+    "child_discardable_shared_memory_manager.h",
+  ]
+
+  deps = [
+    "//base",
+    "//components/discardable_memory/common",
+  ]
+}