Attempt 2 to enable async data: URL loading.

content/test/frame_load_waiter.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 CONTENT_TEST_FRAME_LOAD_WAITER_H_
+#define CONTENT_TEST_FRAME_LOAD_WAITER_H_
+
+#include "base/macros.h"
+#include "base/run_loop.h"
+#include "content/public/renderer/render_frame_observer.h"
+
+namespace content {
+
+// Helper class to spin the run loop when waiting for a frame load to complete.
+// Blink uses a threaded HTML parser, so it's no longer sufficient to just spin
+// the run loop once to process all pending messages.
+class FrameLoadWaiter : public RenderFrameObserver {
+ public:
+  explicit FrameLoadWaiter(RenderFrame* frame);
+  void Wait();
+
+ private:
+  virtual void DidFinishLoad() OVERRIDE;
+
+  base::RunLoop run_loop_;
+
+  DISALLOW_COPY_AND_ASSIGN(FrameLoadWaiter);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_TEST_FRAME_LOAD_WAITER_H_