Add render frame observer for CopylessPaste

components/copyless_paste/renderer/copyless_paste_agent.h

+// Copyright 2017 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 COMPONENTS_COPYLESS_PASTE_RENDERER_COPYLESS_PASTE_AGENT_H_
+#define COMPONENTS_COPYLESS_PASTE_RENDERER_COPYLESS_PASTE_AGENT_H_
+
+#include "content/public/renderer/render_frame_observer.h"
+
+namespace copyless_paste {
+
+// CopylessPasteAgent triggers metadata extraction, and signals app indexing
+// if the result is non-empty.
+class CopylessPasteAgent : public content::RenderFrameObserver {
+ public:
+  CopylessPasteAgent(content::RenderFrame* render_frame);

[dcheng, 2017/04/02 05:50:34]

nit: explicit

+  ~CopylessPasteAgent() override;
+
+  // content::RenderFrameObserver:
+  void DidMeaningfulLayout(blink::WebMeaningfulLayout layout_type) override;
+  void OnDestruct() override;
+};
+
+}  // namespace copyless_paste
+
+#endif  // COMPONENTS_COPYLESS_PASTE_RENDERER_COPYLESS_PASTE_AGENT_H_