Move Preload() code to MappedFile

net/disk_cache/blockfile/mapped_file.cc

Index: net/disk_cache/blockfile/mapped_file.cc
diff --git a/net/disk_cache/blockfile/mapped_file.cc b/net/disk_cache/blockfile/mapped_file.cc
index 4b0f27fc0972da59294c07d0bb6b45c7575a7e9d..d26cead89aab2064646b598e8b7b0ac5f0520c1e 100644
--- a/net/disk_cache/blockfile/mapped_file.cc
+++ b/net/disk_cache/blockfile/mapped_file.cc
@@ -4,6 +4,10 @@
 
 #include "net/disk_cache/blockfile/mapped_file.h"
 
+#include <algorithm>
+
+#include "base/memory/scoped_ptr.h"
+
 namespace disk_cache {
 
 // Note: Most of this class is implemented in platform-specific files.
@@ -32,4 +36,11 @@ bool MappedFile::Store(const FileBlock* block,
   return Write(block->buffer(), block->size(), offset, callback, completed);
 }
 
+bool MappedFile::Preload() {
+  size_t file_len = GetLength();
+  scoped_ptr<char[]> buf(new char[file_len]);
+  if (!Read(buf.get(), file_len, 0))
+    return false;
+  return true;
+}
 }  // namespace disk_cache