[Memory-UMA] Add ProcessMap, an Identity to Pid map

services/service_manager/public/cpp/identity.h

 // 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.
 
 #ifndef SERVICES_SERVICE_MANAGER_PUBLIC_CPP_IDENTITY_H_
 #define SERVICES_SERVICE_MANAGER_PUBLIC_CPP_IDENTITY_H_
 
 #include <string>
 
+#include "base/hash.h"
+
 namespace service_manager {
 
 // Represents the identity of an application.
 // |name| is the structured name of the application.
 // |instance| is a string that allows to tie a specific instance to another. A
 // typical use case of instance is to control process grouping for a given name.
 class Identity {
  public:
   Identity();
   explicit Identity(const std::string& name);
@@ skipping 15 matching lines @@
   const std::string& instance() const { return instance_; }
 
  private:
   std::string name_;
   std::string user_id_;
   std::string instance_;
 };
 
 }  // namespace service_manager
 
+namespace std {
+
+template <>
+struct hash<service_manager::Identity> {
+  std::size_t operator()(const service_manager::Identity& identity) const {
+    return base::Hash(identity.name() + identity.user_id() +
+                      identity.instance());
+  }
+};
+
+}  // namespace std
+
 #endif  // SERVICES_SERVICE_MANAGER_PUBLIC_CPP_IDENTITY_H_