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

content/browser/frame_host/render_frame_host_impl.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_BROWSER_FRAME_HOST_RENDER_FRAME_HOST_IMPL_H_
 #define CONTENT_BROWSER_FRAME_HOST_RENDER_FRAME_HOST_IMPL_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 229 matching lines @@
 
   // Tracks whether the RenderFrame for this RenderFrameHost has been created in
   // the renderer process.  This is currently only used for subframes.
   // TODO(creis): Use this for main frames as well when RVH goes away.
   void SetRenderFrameCreated(bool created);
 
   // Called for renderer-created windows to resume requests from this frame,
   // after they are blocked in RenderWidgetHelper::CreateNewWindow.
   void Init();
 
+  // Returns true if the frame recently plays an audio.
+  bool IsAudible();

[DaleCurtis, 2017/06/22 00:35:54]

const? Prefer bool is_audible() const { return is_audible_; } for consistency
with the other hacker_style() accessors here.

[lpy, 2017/06/22 02:28:52]

Done.

+  void OnAudioStateChanged(bool audible);
+
   int routing_id() const { return routing_id_; }
 
   // Called when this frame has added a child. This is a continuation of an IPC
   // that was partially handled on the IO thread (to allocate |new_routing_id|),
   // and is forwarded here. The renderer has already been told to create a
   // RenderFrame with |new_routing_id|.
   void OnCreateChildFrame(int new_routing_id,
                           blink::WebTreeScopeType scope,
                           const std::string& frame_name,
                           const std::string& frame_unique_name,
@@ skipping 915 matching lines @@
   std::unique_ptr<WebUIImpl> pending_web_ui_;
   WebUI::TypeID pending_web_ui_type_;
 
   // If true the associated WebUI should be reused when CommitPendingWebUI is
   // called (no pending instance should be set).
   bool should_reuse_web_ui_;
 
   // If true, then the RenderFrame has selected text.
   bool has_selection_;
 
+  // If true, then the RenderFrame is playing audio.
+  bool is_audible_;
+
   // PlzNavigate: The Previews state of the last navigation. This is used during
   // history navigation of subframes to ensure that subframes navigate with the
   // same Previews status as the top-level frame.
   PreviewsState last_navigation_previews_state_;
 
   mojo::Binding<mojom::FrameHostInterfaceBroker>
       frame_host_interface_broker_binding_;
   mojo::AssociatedBinding<mojom::FrameHost> frame_host_associated_binding_;
   mojom::FramePtr frame_;
   mojom::FrameBindingsControlAssociatedPtr frame_bindings_control_;
@@ skipping 60 matching lines @@
 
   // NOTE: This must be the last member.
   base::WeakPtrFactory<RenderFrameHostImpl> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderFrameHostImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_FRAME_HOST_RENDER_FRAME_HOST_IMPL_H_