Remove IPC dependency from base

base/metrics/stats_table.h

Index: base/metrics/stats_table.h
diff --git a/base/metrics/stats_table.h b/base/metrics/stats_table.h
index 49ba79f88ba71a3692b3310ef3f6fa7bff8fc857..719e6304813243332e0b129cc1422d499a075c1e 100644
--- a/base/metrics/stats_table.h
+++ b/base/metrics/stats_table.h
@@ -28,24 +28,45 @@
 #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:
-  // 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.
+  // 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.
   //
-  // name is the name of the StatsTable to use.
+  // 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.
   //
   // 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.