[Memory-UMA] Implement basic working prototype.

services/resource_coordinator/public/interfaces/memory/memory_instrumentation.mojom

 // 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.
 
 module memory_instrumentation.mojom;
 
 import "mojo/common/process_id.mojom";
 
 enum DumpType {
   PERIODIC_INTERVAL,
@@ skipping 45 matching lines @@
 
 // This struct is used both for:
 // 1) The internal communication between the memory service (Coordinator) and
 //    the client library (ProcessLocalDumpManager).
 // 2) The public-facing API Coordinator::RequestGlobalMemoryDump().
 struct ProcessMemoryDump {
   ProcessType process_type;
   OSMemDump os_dump;
   ChromeMemDump chrome_dump;
 
-  // TODO(hjd): add the computed Consistent Memory Metrics footprints here.
+  // This is roughly private, anonymous, non-discardable, resident or swapped
+  // memory. For more details, see https://goo.gl/3kPb9S.
+  uint32 private_footprint = 0;
 
   // This is used only in the use-case (1) and only on Linux/CrOS to get
   // around sandboxing. See crbug.com/461788 .
   map<mojo.common.mojom.ProcessId, OSMemDump> extra_processes_dump;
 };
 
 
 // This struct is returned by the public-facing API
 // Coordinator::RequestGlobalMemoryDump().
 struct GlobalMemoryDump {
@@ skipping 16 matching lines @@
   // Used to register a client library to obtain a process-local dump from it
   // when RequestGlobalMemoryDump() is called.
   RegisterProcessLocalDumpManager(ProcessLocalDumpManager local_manager);
 
   // Broadcasts a dump request to all registered client libraries, injects the
   // dump in the trace buffer (if tracing is enabled) and returns a summarized
   // dump back if args.dump_type == SUMMARY_ONLY.
   RequestGlobalMemoryDump(RequestArgs args) =>
       (uint64 dump_guid, bool success, GlobalMemoryDump? global_memory_dump);
 };