Add support for multiple zygote fork delegates

content/zygote/zygote_linux.h

 // Copyright (c) 2012 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 CONTENT_ZYGOTE_ZYGOTE_H_
 #define CONTENT_ZYGOTE_ZYGOTE_H_
 
+#include <stddef.h>
+
 #include <string>
 
 #include "base/containers/small_map.h"
 #include "base/files/scoped_file.h"
 #include "base/memory/scoped_vector.h"
 #include "base/posix/global_descriptors.h"
 #include "base/process/kill.h"
 #include "base/process/process.h"
 
 class Pickle;
 class PickleIterator;
 
 namespace content {
 
 class ZygoteForkDelegate;
 
 // This is the object which implements the zygote. The ZygoteMain function,
 // which is called from ChromeMain, simply constructs one of these objects and
 // runs it.
 class Zygote {
  public:
-  Zygote(int sandbox_flags,
-         ZygoteForkDelegate* helper);
+  Zygote(int sandbox_flags, ScopedVector<ZygoteForkDelegate> helpers);
   ~Zygote();
 
   bool ProcessRequests();
 
  private:
   struct ZygoteProcessInfo {
     // Pid from inside the Zygote's PID namespace.
     base::ProcessHandle internal_pid;
-    // Keeps track of whether or not a process was started from a fork
-    // delegate helper.
-    bool started_from_helper;
+    // Keeps track of which fork delegate helper the process was started from.
+    ZygoteForkDelegate* started_from_helper;
   };
   typedef base::SmallMap< std::map<base::ProcessHandle, ZygoteProcessInfo> >
       ZygoteProcessMap;
 
   // Retrieve a ZygoteProcessInfo from the process_info_map_.
   // Returns true and write to process_info if |pid| can be found, return
   // false otherwise.
   bool GetProcessInfo(base::ProcessHandle pid,
                       ZygoteProcessInfo* process_info);
 
@@ skipping 60 matching lines @@
                               const Pickle& pickle,
                               PickleIterator iter);
 
   // The Zygote needs to keep some information about each process. Most
   // notably what the PID of the process is inside the PID namespace of
   // the Zygote and whether or not a process was started by the
   // ZygoteForkDelegate helper.
   ZygoteProcessMap process_info_map_;
 
   const int sandbox_flags_;
-  ZygoteForkDelegate* helper_;
+  ScopedVector<ZygoteForkDelegate> helpers_;
 
-  // These might be set by helper_->InitialUMA. They supply a UMA enumeration
-  // sample we should report on the first fork.
-  std::string initial_uma_name_;
-  int initial_uma_sample_;
-  int initial_uma_boundary_value_;
+  // Count of how many fork delegates for which we've invoked InitialUMA().
+  size_t initial_uma_index_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_ZYGOTE_ZYGOTE_H_