Put the RenderFrame's ID into a per-frame WebBluetooth, and plumb that back to the browser.

content/renderer/render_frame_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_RENDERER_RENDER_FRAME_IMPL_H_
 #define CONTENT_RENDERER_RENDER_FRAME_IMPL_H_
 
 #include <vector>
 
 #include "base/basictypes.h"
@@ skipping 528 matching lines @@
   virtual void didChangeDefaultPresentation(blink::WebLocalFrame*);
   virtual bool enterFullscreen();
   virtual bool exitFullscreen();
   virtual blink::WebPermissionClient* permissionClient();
   virtual blink::WebAppBannerClient* appBannerClient();
   virtual void registerProtocolHandler(const blink::WebString& scheme,
                                        const blink::WebURL& url,
                                        const blink::WebString& title);
   virtual void unregisterProtocolHandler(const blink::WebString& scheme,
                                          const blink::WebURL& url);
+  virtual blink::WebBluetooth* bluetooth();
 
 #if defined(ENABLE_WEBVR)
   blink::WebVRClient* webVRClient() override;
 #endif
 
   // WebMediaPlayerDelegate implementation:
   void DidPlay(blink::WebMediaPlayer* player) override;
   void DidPause(blink::WebMediaPlayer* player) override;
   void PlayerGone(blink::WebMediaPlayer* player) override;
 
@@ skipping 436 matching lines @@
   AccessibilityMode accessibility_mode_;
 
   // Only valid if |accessibility_mode_| is anything other than
   // AccessibilityModeOff.
   RendererAccessibility* renderer_accessibility_;
 
   scoped_ptr<PermissionDispatcher> permission_client_;
 
   scoped_ptr<blink::WebAppBannerClient> app_banner_client_;
 
+  scoped_ptr<blink::WebBluetooth> bluetooth_;
+
 #if defined(ENABLE_WEBVR)
   // The VR dispatcher attached to the frame, lazily initialized.
   scoped_ptr<VRDispatcher> vr_dispatcher_;
 #endif
 
 #if defined(OS_MACOSX) || defined(OS_ANDROID)
   // The external popup for the currently showing select popup.
   scoped_ptr<ExternalPopupMenu> external_popup_menu_;
 #endif
 
   base::WeakPtrFactory<RenderFrameImpl> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderFrameImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_RENDER_FRAME_IMPL_H_