Allow BlobDataHandles to be copied, and have their UUIDs read, on any thread.

webkit/browser/blob/blob_data_handle.h

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef WEBKIT_BROWSER_BLOB_BLOB_DATA_HANDLE_H_
 #define WEBKIT_BROWSER_BLOB_BLOB_DATA_HANDLE_H_
 
 #include <string>
 
 #include "base/memory/ref_counted.h"
@@ skipping 10 matching lines @@
 class BlobData;
 class BlobStorageContext;
 
 // A scoper object for use in chrome's main browser process, ensures
 // the underlying BlobData and its uuid remain in BlobStorageContext's
 // collection for the duration. This object has delete semantics and
 // maybe deleted on any thread.
 class WEBKIT_STORAGE_BROWSER_EXPORT BlobDataHandle
     : public base::SupportsUserData::Data {
  public:
+  BlobDataHandle(const BlobDataHandle& other);  // May be copied on any thread.
   virtual ~BlobDataHandle();  // Maybe be deleted on any thread.
   BlobData* data() const;  // May only be accessed on the IO thread.
 
+  std::string uuid() const;  // May be accessed on any thread.
+
  private:
+  class BlobDataHandleShared

[michaeln, 2014/04/28 18:25:22]

too bad this has to be in the .h file :(

+      : public base::RefCountedThreadSafe<BlobDataHandleShared> {
+   public:
+    BlobDataHandleShared(BlobData* blob_data,
+                         BlobStorageContext* context,
+                         base::SequencedTaskRunner* task_runner);
+
+    BlobData* data() const;
+    const std::string& uuid() const;
+
+   private:
+    friend class base::DeleteHelper<BlobDataHandleShared>;
+    friend class base::RefCountedThreadSafe<BlobDataHandleShared>;
+    friend class BlobDataHandle;
+
+    virtual ~BlobDataHandleShared();
+
+    scoped_refptr<BlobData> blob_data_;
+    base::WeakPtr<BlobStorageContext> context_;
+    scoped_refptr<base::SequencedTaskRunner> io_task_runner_;
+
+    DISALLOW_COPY_AND_ASSIGN(BlobDataHandleShared);
+  };
+
   friend class BlobStorageContext;
   BlobDataHandle(BlobData* blob_data, BlobStorageContext* context,
                  base::SequencedTaskRunner* task_runner);
 
-  static void DeleteHelper(
-      base::WeakPtr<BlobStorageContext> context,
-      BlobData* blob_data);
-
-  BlobData* blob_data_;  // Intentionally a raw ptr to a non-thread-safe ref.
-  base::WeakPtr<BlobStorageContext> context_;
   scoped_refptr<base::SequencedTaskRunner> io_task_runner_;
-
-  DISALLOW_COPY_AND_ASSIGN(BlobDataHandle);
+  scoped_refptr<BlobDataHandleShared> shared_;
 };
 
 }  // namespace webkit_blob
 
 #endif  // WEBKIT_BROWSER_BLOB_BLOB_DATA_HANDLE_H_