[SimpleCache] Prefetch stream 1 so that the first read is faster

net/disk_cache/simple/simple_entry_impl.h

Index: net/disk_cache/simple/simple_entry_impl.h
diff --git a/net/disk_cache/simple/simple_entry_impl.h b/net/disk_cache/simple/simple_entry_impl.h
index 4cb1019f9ac81f2769357c73ae96a27f6b4b324e..9280d61ce5ddf2bddfeecf8a8bd28a8b1b1e809e 100644
--- a/net/disk_cache/simple/simple_entry_impl.h
+++ b/net/disk_cache/simple/simple_entry_impl.h
@@ -391,6 +391,11 @@ class NET_EXPORT_PRIVATE SimpleEntryImpl : public Entry,
   // used to write HTTP headers, the memory consumption of keeping it in memory
   // is acceptable.
   scoped_refptr<net::GrowableIOBuffer> stream_0_data_;
+
+  // Some stream 1 data is prefetched when stream 0 is first read, to make the
+  // first read call on stream 1 synchronous. If a write to any stream occurs
+  // on the entry the prefetch buffer is no longer used.
+  scoped_refptr<net::GrowableIOBuffer> stream_1_prefetch_data_;
 };
 
 }  // namespace disk_cache