Move Preload() code to MappedFile

net/disk_cache/blockfile/block_files.cc

Index: net/disk_cache/blockfile/block_files.cc
diff --git a/net/disk_cache/blockfile/block_files.cc b/net/disk_cache/blockfile/block_files.cc
index 3f4bbf5274c3212d812f5b87ef7502ef65649bb7..ac6114ee746b7b3595ef23a4027d5655fe9c7888 100644
--- a/net/disk_cache/blockfile/block_files.cc
+++ b/net/disk_cache/blockfile/block_files.cc
@@ -508,9 +508,8 @@ bool BlockFiles::OpenBlockFile(int index) {
   }
 
   if (index == 0) {
-    // Load the links file into memory with a single read.
-    scoped_ptr<char[]> buf(new char[file_len]);
-    if (!file->Read(buf.get(), file_len, 0))
+    // Load the links file into memory.
+    if (!file->Preload())
       return false;
   }