Blobs: Catching browser-process created Blobs in extension code.

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;
+class RenderViewHost;
+}
+
+namespace extensions {
+
+// Used for holding onto Blobs created into the browser process until a
+// renderer takes over ownership. Each Blob is associated with a specific
+// RenderViewHost. If the RenderViewHost is deleted before it can take ownership
+// of the Blob, the Blob reference is released.
+class BlobHolder : public content::WebContentsObserver,
+                   public content::WebContentsUserData<BlobHolder> {
+ public:
+  virtual ~BlobHolder();
+
+  void HoldBlobReference(content::RenderViewHost* render_view_host,
+                         scoped_ptr<content::BlobHandle> blob);
+
+ private:
+  struct BlobHolderData;
+
+  explicit BlobHolder(content::WebContents* web_contents);
+  friend class content::WebContentsUserData<BlobHolder>;
+
+  bool ContainsUUID(const std::string& uuid) const;
+
+  // content::WebContentsObserver overrides.
+  // Releases all the Blob references associated with this render_view_host.
+  virtual void RenderViewDeleted(
+      content::RenderViewHost* render_view_host) OVERRIDE;
+  virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
+
+  // Message handlers.
+  void OnBlobOwnershipTaken(const std::string& uuid);
+
+  // The BlobHandles associated with each RenderViewHost.
+  ScopedVector<BlobHolderData> held_blobs_;
+
+  DISALLOW_COPY_AND_ASSIGN(BlobHolder);
+};
+
+}  // namespace extensions
+
+#endif  // CHROME_BROWSER_EXTENSIONS_BLOB_HOLDER_H_