Create blobs from Disk Cache entries.

storage/common/data_element.h

Index: storage/common/data_element.h
diff --git a/storage/common/data_element.h b/storage/common/data_element.h
index 0efe1550a91e9a509d1cc0548854167a58c3a689..4184f993aa120b887051999280bec6b1098a0f53 100644
--- a/storage/common/data_element.h
+++ b/storage/common/data_element.h
@@ -27,6 +27,7 @@ class STORAGE_COMMON_EXPORT DataElement {
     TYPE_FILE,
     TYPE_BLOB,
     TYPE_FILE_FILESYSTEM,
+    TYPE_DISK_CACHE_ENTRY,
   };
 
   DataElement();
@@ -102,13 +103,16 @@ class STORAGE_COMMON_EXPORT DataElement {
                                uint64 offset, uint64 length,
                                const base::Time& expected_modification_time);
 
+  // Sets to TYPE_DISK_CACHE_ENTRY.
+  void SetToDiskCacheEntry();
+
  private:
   Type type_;
   std::vector<char> buf_;  // For TYPE_BYTES.
   const char* bytes_;  // For TYPE_BYTES.
   base::FilePath path_;  // For TYPE_FILE.
   GURL filesystem_url_;  // For TYPE_FILE_FILESYSTEM.
-  std::string blob_uuid_;
+  std::string blob_uuid_;  // For TYPE_BLOB.
   uint64 offset_;
   uint64 length_;
   base::Time expected_modification_time_;
@@ -130,6 +134,8 @@ inline bool operator==(const DataElement& a, const DataElement& b) {
       return a.blob_uuid() == b.blob_uuid();
     case DataElement::TYPE_FILE_FILESYSTEM:
       return a.filesystem_url() == b.filesystem_url();
+    case DataElement::TYPE_DISK_CACHE_ENTRY:
+      return true;  // These have no data, so they're always equal.
     case DataElement::TYPE_UNKNOWN:
       NOTREACHED();
       return false;