Move Preload() code to MappedFile

net/disk_cache/blockfile/backend_impl.cc

Index: net/disk_cache/blockfile/backend_impl.cc
diff --git a/net/disk_cache/blockfile/backend_impl.cc b/net/disk_cache/blockfile/backend_impl.cc
index 85c4e36c1f3c5fff79290b0180e6db9d9ccfeae1..af84b10f169e3d3e4570f0def5f5fd31dc475fef 100644
--- a/net/disk_cache/blockfile/backend_impl.cc
+++ b/net/disk_cache/blockfile/backend_impl.cc
@@ -1285,7 +1285,7 @@ bool BackendImpl::InitBackingStore(bool* file_created) {
     return false;
 
   index_ = new MappedFile();
-  data_ = reinterpret_cast<Index*>(index_->Init(index_name, 0));
+  data_ = static_cast<Index*>(index_->Init(index_name, 0));
   if (!data_) {
     LOG(ERROR) << "Unable to map Index file";
     return false;
@@ -2016,9 +2016,8 @@ bool BackendImpl::CheckIndex() {
   if (!mask_)
     mask_ = data_->header.table_len - 1;
 
-  // Load the table into memory with a single read.
-  scoped_ptr<char[]> buf(new char[current_size]);
-  return index_->Read(buf.get(), current_size, 0);
+  // Load the table into memory.
+  return index_->Preload();
 }
 
 int BackendImpl::CheckAllEntries() {