Blobs: Mechanism for creating Blobs in browser process, then transferring to renderer.

chrome/browser/extensions/blob_holder.h

+// Copyright 2014 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 CHROME_BROWSER_EXTENSIONS_BLOB_HOLDER_H_
+#define CHROME_BROWSER_EXTENSIONS_BLOB_HOLDER_H_
+
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/scoped_vector.h"
+#include "content/public/browser/web_contents_observer.h"
+#include "content/public/browser/web_contents_user_data.h"
+
+namespace content {
+class BlobHandle;
+}
+
+namespace extensions {
+
+// Used for holding onto Blobs created into the browser process until a
+// renderer takes over ownership.
+class BlobHolder : public content::WebContentsObserver,
+                   public content::WebContentsUserData<BlobHolder> {
+ public:
+  virtual ~BlobHolder();
+
+  void HoldBlobReference(scoped_ptr<content::BlobHandle> blob);
+
+ private:
+  explicit BlobHolder(content::WebContents* web_contents);
+  friend class content::WebContentsUserData<BlobHolder>;
+
+  // content::WebContentsObserver overrides.
+  virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
+
+  // Message handlers.
+  void OnBlobOwnershipTaken(const std::string& uuid);
+
+  ScopedVector<content::BlobHandle> held_blobs_;
+
+  DISALLOW_COPY_AND_ASSIGN(BlobHolder);
+};
+
+}  // namespace extensions
+
+#endif  // CHROME_BROWSER_EXTENSIONS_BLOB_HOLDER_H_