[AudioStreamMonitor] Adds API to collect frame-level audibility.

content/public/browser/render_frame_host.h

 // Copyright 2013 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_PUBLIC_BROWSER_RENDER_FRAME_HOST_H_
 #define CONTENT_PUBLIC_BROWSER_RENDER_FRAME_HOST_H_
 
 #include <string>
 
 #include "base/callback_forward.h"
@@ skipping 222 matching lines @@
   // Notifies the Listener that one or more files have been chosen by the user
   // from a file chooser dialog for the form. |permissions| is the file
   // selection mode in which the chooser dialog was created.
   virtual void FilesSelectedInChooser(
       const std::vector<content::FileChooserFileInfo>& files,
       FileChooserParams::Mode permissions) = 0;
 
   // Returns true if the frame has a selection.
   virtual bool HasSelection() = 0;
 
+  // Returns true if the frame recently plays an audio.
+  virtual bool IsAudible() = 0;
+  virtual void OnAudioStateChanged(bool audible) = 0;

[nasko, 2017/06/20 16:17:45]

These APIs are not used outside of content/, so they should not be added to the
public RenderFrameHost interface, but kept internally only on
RenderFrameHostImpl.

[lpy, 2017/06/20 22:28:53]

Done.

+
   // Text surrounding selection.
   typedef base::Callback<
       void(const base::string16& content, int start_offset, int end_offset)>
       TextSurroundingSelectionCallback;
   virtual void RequestTextSurroundingSelection(
       const TextSurroundingSelectionCallback& callback,
       int max_length) = 0;
 
   // Tell the render frame to enable a set of javascript bindings. The argument
   // should be a combination of values from BindingsPolicy.
@@ skipping 35 matching lines @@
 
  private:
   // This interface should only be implemented inside content.
   friend class RenderFrameHostImpl;
   RenderFrameHost() {}
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_RENDER_FRAME_HOST_H_