Simple Cache: Add two optional stream 2 histograms

net/disk_cache/simple/simple_index_file.h

 // Copyright (c) 2013 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 NET_DISK_CACHE_SIMPLE_SIMPLE_INDEX_FILE_H_
 #define NET_DISK_CACHE_SIMPLE_SIMPLE_INDEX_FILE_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 22 matching lines @@
   SimpleIndexLoadResult();
   ~SimpleIndexLoadResult();
   void Reset();
 
   bool did_load;
   SimpleIndex::EntrySet entries;
   bool flush_required;
 };
 
 // Simple Index File format is a pickle serialized data of IndexMetadata and
-// EntryMetadata objects.  The file format is as follows: one instance of
+// EntryMetadata objects. The file format is as follows: one instance of
 // serialized |IndexMetadata| followed serialized |EntryMetadata| entries
-// repeated |number_of_entries| amount of times.  To know more about the format,
+// repeated |number_of_entries| amount of times. To know more about the format,
 // see SimpleIndexFile::Serialize() and SeeSimpleIndexFile::LoadFromDisk()
 // methods.
 //
-// The non-static methods must run on the IO thread.  All the real
+// The non-static methods must run on the IO thread. All the real
 // work is done in the static methods, which are run on the cache thread
-// or in worker threads.  Synchronization between methods is the
+// or in worker threads. Synchronization between methods is the
 // responsibility of the caller.
 class NET_EXPORT_PRIVATE SimpleIndexFile {
  public:
   class NET_EXPORT_PRIVATE IndexMetadata {
    public:
     IndexMetadata();
     IndexMetadata(uint64 number_of_entries, uint64 cache_size);
 
     void Serialize(Pickle* pickle) const;
     bool Deserialize(PickleIterator* it);
@@ skipping 117 matching lines @@
   static const char kIndexFileName[];
   static const char kTempIndexFileName[];
 
   DISALLOW_COPY_AND_ASSIGN(SimpleIndexFile);
 };
 
 
 }  // namespace disk_cache
 
 #endif  // NET_DISK_CACHE_SIMPLE_SIMPLE_INDEX_FILE_H_