Refactor cache counting into a separate helper class

net/disk_cache/simple/simple_entry_impl.cc

Index: net/disk_cache/simple/simple_entry_impl.cc
diff --git a/net/disk_cache/simple/simple_entry_impl.cc b/net/disk_cache/simple/simple_entry_impl.cc
index 23136ba60e541c91b9d5cfccfe0bffb1651df214..37a3d2ec78fa325f55c76c46bcb64249240099c9 100644
--- a/net/disk_cache/simple/simple_entry_impl.cc
+++ b/net/disk_cache/simple/simple_entry_impl.cc
@@ -344,6 +344,10 @@ int32_t SimpleEntryImpl::GetDataSize(int stream_index) const {
   return data_size_[stream_index];
 }
 
+int64_t SimpleEntryImpl::GetEntrySize() const {
+  return GetDiskUsage();
+}
+
 int SimpleEntryImpl::ReadData(int stream_index,
                               int offset,
                               net::IOBuffer* buf,