Create blobs from Disk Cache entries.

storage/browser/blob/blob_data_item.cc

Index: storage/browser/blob/blob_data_item.cc
diff --git a/storage/browser/blob/blob_data_item.cc b/storage/browser/blob/blob_data_item.cc
index 504a1c3e8be39939d58c0ac19702f7c6d3e2ac89..c1ec3b3db68fadb7930d5cdcb022610cbb924037 100644
--- a/storage/browser/blob/blob_data_item.cc
+++ b/storage/browser/blob/blob_data_item.cc
@@ -6,12 +6,33 @@
 
 namespace storage {
 
+BlobDataItem::DataHandle::~DataHandle() {
+}
+
+BlobDataItem::BlobDataItem(scoped_ptr<DataElement> item)
+    : item_(item.Pass()),
+      disk_cache_entry_(nullptr),
+      disk_cache_stream_index_(-1) {
+}
+
 BlobDataItem::BlobDataItem(scoped_ptr<DataElement> item,
-                           scoped_refptr<ShareableFileReference> file_handle)
-    : item_(item.Pass()), file_handle_(file_handle) {
+                           const scoped_refptr<DataHandle>& data_handle)
+    : item_(item.Pass()),
+      data_handle_(data_handle),
+      disk_cache_entry_(nullptr),
+      disk_cache_stream_index_(-1) {
 }
-BlobDataItem::BlobDataItem(scoped_ptr<DataElement> item) : item_(item.Pass()) {
+
+BlobDataItem::BlobDataItem(scoped_ptr<DataElement> item,

[mmenke, 2015/06/17 19:11:16]

What's the conceptual distinction between a BlobDataItem and DataElement?

Just wondering on the motivation for putting the disk_cache_stream_index and
entry here, rather than in there.  Having only one class know that this is
really a disk cache entry seems a bit cleaner.

[dmurph, 2015/06/17 20:18:06]

DataElement is legacy and is used in other parts of the system.  Specifically,
for IPC serialization, and needs to be copy-able.  This is probably going to
eventually be removed in favor of storing member variables in BlobDataItem. 
This system is in the middle of a refactor, this is one of the current
carry-overs that hasn't been removed.

We can add a "TODO(dmurph): Migrate DataElement fields into BlobDataItem"

+                           const scoped_refptr<DataHandle>& data_handle,
+                           disk_cache::Entry* entry,
+                           int disk_cache_stream_index)
+    : item_(item.Pass()),
+      data_handle_(data_handle),
+      disk_cache_entry_(entry),
+      disk_cache_stream_index_(disk_cache_stream_index) {
 }
+
 BlobDataItem::~BlobDataItem() {
 }