Fix Mac build after https://codereview.chromium.org/1407643004

snapshot/mac/process_snapshot_mac.h

 // Copyright 2014 The Crashpad Authors. All rights reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
@@ skipping 110 matching lines @@
   void ProcessCPUTimes(timeval* user_time, timeval* system_time) const override;
   void ReportID(UUID* report_id) const override;
   void ClientID(UUID* client_id) const override;
   const std::map<std::string, std::string>& AnnotationsSimpleMap()
       const override;
   const SystemSnapshot* System() const override;
   std::vector<const ThreadSnapshot*> Threads() const override;
   std::vector<const ModuleSnapshot*> Modules() const override;
   const ExceptionSnapshot* Exception() const override;
   std::vector<const MemoryMapRegionSnapshot*> MemoryMap() const override;
+  std::vector<HandleSnapshot> Handles() const override;
   std::vector<const MemorySnapshot*> ExtraMemory() const override;
 
  private:
   // Initializes threads_ on behalf of Initialize().
   void InitializeThreads();
 
   // Initializes modules_ on behalf of Initialize().
   void InitializeModules();
 
   internal::SystemSnapshotMac system_;
   PointerVector<internal::ThreadSnapshotMac> threads_;
   PointerVector<internal::ModuleSnapshotMac> modules_;
   scoped_ptr<internal::ExceptionSnapshotMac> exception_;
   ProcessReader process_reader_;
   UUID report_id_;
   UUID client_id_;
   std::map<std::string, std::string> annotations_simple_map_;
   timeval snapshot_time_;
   InitializationStateDcheck initialized_;
 
   DISALLOW_COPY_AND_ASSIGN(ProcessSnapshotMac);
 };
 
 }  // namespace crashpad
 
 #endif  // CRASHPAD_SNAPSHOT_MAC_PROCESS_SNAPSHOT_MAC_H_