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

content/child/bluetooth/web_bluetooth_impl.cc

Index: content/child/bluetooth/web_bluetooth_impl.cc
diff --git a/content/child/bluetooth/web_bluetooth_impl.cc b/content/child/bluetooth/web_bluetooth_impl.cc
index c307461a5345fe98d311dd38defbf9fbe3c55ba8..d15ed2fa146bdf60d8a9a48a996e91cbadfeb5bd 100644
--- a/content/child/bluetooth/web_bluetooth_impl.cc
+++ b/content/child/bluetooth/web_bluetooth_impl.cc
@@ -6,11 +6,17 @@
 
 #include "content/child/bluetooth/bluetooth_dispatcher.h"
 #include "content/child/thread_safe_sender.h"
+#include "ipc/ipc_message.h"
 
 namespace content {
 
 WebBluetoothImpl::WebBluetoothImpl(ThreadSafeSender* thread_safe_sender)
-    : thread_safe_sender_(thread_safe_sender) {
+    : WebBluetoothImpl(thread_safe_sender, MSG_ROUTING_NONE) {
+}
+
+WebBluetoothImpl::WebBluetoothImpl(ThreadSafeSender* thread_safe_sender,
+                                   int routing_id)
+    : thread_safe_sender_(thread_safe_sender), routing_id_(routing_id) {
 }
 
 WebBluetoothImpl::~WebBluetoothImpl() {
@@ -19,7 +25,7 @@ WebBluetoothImpl::~WebBluetoothImpl() {
 void WebBluetoothImpl::requestDevice(
     const blink::WebRequestDeviceOptions& options,
     blink::WebBluetoothRequestDeviceCallbacks* callbacks) {
-  GetDispatcher()->requestDevice(options, callbacks);
+  GetDispatcher()->requestDevice(routing_id_, options, callbacks);
 }
 
 void WebBluetoothImpl::connectGATT(const blink::WebString& device_instance_id,