Implements frame sniffer to watch iframe loading state.

chrome/renderer/frame_sniffer.h

Index: chrome/renderer/frame_sniffer.h
diff --git a/chrome/renderer/frame_sniffer.h b/chrome/renderer/frame_sniffer.h
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+// 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 CHROME_RENDERER_FRAME_SNIFFER_H_
+#define CHROME_RENDERER_FRAME_SNIFFER_H_
+
+#include "base/basictypes.h"
+#include "base/compiler_specific.h"
+#include "content/renderer/render_view_observer.h"
+
+// Class which observes events from the frame with specific name and sends IPC
+// messages to be handled by RenderViewHostObserver.
+class FrameSniffer : public RenderViewObserver {
+ public:
+  FrameSniffer(RenderView* render_view, const string16 &frame_name);
+  virtual ~FrameSniffer();
+
+  // Implements RenderViewObserver.
+  virtual void DidFailProvisionalLoad(
+      WebKit::WebFrame* frame, const WebKit::WebURLError& error) OVERRIDE;
+
+ private:
+  bool ShouldSniffFrame(WebKit::WebFrame* frame);
+
+  // Name of the frame to be monitored.
+  string16 frame_name_;
+
+  DISALLOW_COPY_AND_ASSIGN(FrameSniffer);
+};
+
+#endif  // CHROME_RENDERER_FRAME_SNIFFER_H_