Support getting the font list in Pepper. This currently only works out of

content/browser/font_list_async.h

+// Copyright (c) 2011 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 CONTENT_BROWSER_FONT_LIST_ASYNC_H_
+#define CONTENT_BROWSER_FONT_LIST_ASYNC_H_
+
+#include "base/callback.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+
+class ListValue;
+
+namespace content {
+
+// Wraps ownership of a ListValue so we can send it across threads without
+// having ownership problems (for example if the calling thread goes away
+// before the callback is executed, we want the ListValue to be destroyed.
+struct FontListResult : public base::RefCountedThreadSafe<FontListResult> {
+  FontListResult();
+  ~FontListResult();
+
+  scoped_ptr<ListValue> list;
+};
+
+// Retrieves the list of fonts on the system as a list of strings. It provides
+// a non-blocking interface to GetFontList_SlowBlocking in common/.
+//
+// This function will run asynchronously on a background thread since getting
+// the font list from the system can be slow. This function may be called from
+// any thread that has a BrowserThread::ID. The callback will be executed on
+// the calling thread.
+//
+// If the caller wants to take ownership of the ListValue, it can just do
+// FontListResult.list.release() or use scoped_ptr.swap() because this value
+// isn't used for anything else.
+void GetFontListAsync(
+    const base::Callback<void(scoped_refptr<FontListResult>)>& callback);
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_FONT_LIST_ASYNC_H_