Remove IPC dependency from base

base/metrics/stats_table.h

 // Copyright (c) 2011 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.
 //
 // A StatsTable is a table of statistics.  It can be used across multiple
 // processes and threads, maintaining cheap statistics counters without
 // locking.
 //
 // The goal is to make it very cheap and easy for developers to add
 // counters to code, without having to build one-off utilities or mechanisms
@@ skipping 10 matching lines @@
 #define BASE_METRICS_STATS_TABLE_H_
 
 #include <string>
 
 #include "base/base_export.h"
 #include "base/basictypes.h"
 #include "base/containers/hash_tables.h"
 #include "base/memory/shared_memory.h"
 #include "base/synchronization/lock.h"
 #include "base/threading/thread_local_storage.h"
+#include "build/build_config.h"
+
+#if defined(OS_POSIX)
+#include "base/file_descriptor_posix.h"
+#endif
 
 namespace base {
 
 class BASE_EXPORT StatsTable {
  public:
+  // Identifies a StatsTable. We often want to share these between processes.
+  //
+  // On Windows, we use a named shared memory segment so the table identifier
+  // should be a relatively unique string identifying the table to use. An
+  // empty string can be used to use an anonymous shared memory segment for
+  // cases where the table does not need to be shared between processes.
+  //
+  // Posix does not support named memory so we explicitly share file
+  // descriptors. On Posix, pass a default-constructed file descriptor if a
+  // handle doesn't already exist, and a new one will be created.
+  //
+  // If a table doesn't already exist with the given identifier, a new one will
+  // be created with zeroed counters.
+#if defined(OS_POSIX)
+  typedef FileDescriptor TableIdentifier;
+#elif defined(OS_WIN)
+  typedef std::string TableIdentifier;
+#endif
+
   // Create a new StatsTable.
-  // If a StatsTable already exists with the specified name, this StatsTable
-  // will use the same shared memory segment as the original.  Otherwise,
-  // a new StatsTable is created and all counters are zeroed.
-  //
-  // name is the name of the StatsTable to use.
   //
   // max_threads is the maximum number of threads the table will support.
   // If the StatsTable already exists, this number is ignored.
   //
   // max_counters is the maximum number of counters the table will support.
   // If the StatsTable already exists, this number is ignored.
-  StatsTable(const std::string& name, int max_threads, int max_counters);
+  StatsTable(const TableIdentifier& table,
+             int max_threads,
+             int max_counters);
 
   // Destroys the StatsTable.  When the last StatsTable is destroyed
   // (across all processes), the StatsTable is removed from disk.
   ~StatsTable();
 
   // For convenience, we create a static table.  This is generally
   // used automatically by the counters.
   static StatsTable* current();
 
   // Set the global table for use in this process.
@@ skipping 131 matching lines @@
   // have created it.
   CountersMap counters_;
   ThreadLocalStorage::Slot tls_index_;
 
   DISALLOW_COPY_AND_ASSIGN(StatsTable);
 };
 
 }  // namespace base
 
 #endif  // BASE_METRICS_STATS_TABLE_H_