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

content/browser/bluetooth/bluetooth_dispatcher_host.cc

Index: content/browser/bluetooth/bluetooth_dispatcher_host.cc
diff --git a/content/browser/bluetooth/bluetooth_dispatcher_host.cc b/content/browser/bluetooth/bluetooth_dispatcher_host.cc
index f35103dfd1ebef5f254217bc9e0cb34440efa2be..5e4853d54d4d9a120b44e2c54bddaeb4deca235e 100644
--- a/content/browser/bluetooth/bluetooth_dispatcher_host.cc
+++ b/content/browser/bluetooth/bluetooth_dispatcher_host.cc
@@ -13,6 +13,7 @@
 #include "base/metrics/histogram.h"
 #include "base/strings/utf_string_conversions.h"
 #include "content/browser/bad_message.h"
+#include "content/browser/frame_host/render_frame_host_impl.h"
 #include "content/common/bluetooth/bluetooth_messages.h"
 #include "device/bluetooth/bluetooth_adapter.h"
 #include "device/bluetooth/bluetooth_adapter_factory.h"
@@ -135,8 +136,9 @@ blink::WebBluetoothError TranslateGATTError(
 
 namespace content {
 
-BluetoothDispatcherHost::BluetoothDispatcherHost()
+BluetoothDispatcherHost::BluetoothDispatcherHost(int render_process_id)
     : BrowserMessageFilter(BluetoothMsgStart),
+      render_process_id_(render_process_id),
       weak_ptr_factory_(this) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   current_delay_time_ = kDelayTime;
@@ -187,10 +189,14 @@ BluetoothDispatcherHost::~BluetoothDispatcherHost() {
 }
 
 struct BluetoothDispatcherHost::RequestDeviceSession {
-  RequestDeviceSession(const std::vector<BluetoothScanFilter>& filters,
+  RequestDeviceSession(int frame_routing_id,

[ortuno, 2015/07/15 23:00:46]

This is called frame_routing_id but you call it routing_id.

[Jeffrey Yasskin, 2015/07/17 01:32:44]

Yep, this is undone now that it's no longer coming from content/child.

+                       const std::vector<BluetoothScanFilter>& filters,
                        const std::vector<BluetoothUUID>& optional_services)
-      : filters(filters), optional_services(optional_services) {}
+      : frame_routing_id(frame_routing_id),
+        filters(filters),
+        optional_services(optional_services) {}
 
+  int frame_routing_id;

[scheib, 2015/07/16 01:11:46]

Perhaps add it when we need it? Or if you have a follow up patch that uses it
OK, but would be good to see that patch draft.

[Jeffrey Yasskin, 2015/07/17 01:32:44]

I've undone this storage. We'll see how it needs to be stored when I wire up the
dialog.

   std::vector<BluetoothScanFilter> filters;
   std::vector<BluetoothUUID> optional_services;
 };
@@ -223,16 +229,29 @@ static scoped_ptr<device::BluetoothDiscoveryFilter> ComputeScanFilter(
 void BluetoothDispatcherHost::OnRequestDevice(
     int thread_id,
     int request_id,
+    int routing_id,
     const std::vector<BluetoothScanFilter>& filters,
     const std::vector<BluetoothUUID>& optional_services) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+
+  RenderFrameHostImpl* render_frame_host =
+      RenderFrameHostImpl::FromID(render_process_id_, routing_id);
+
+  if (!render_frame_host) {
+    DLOG(WARNING)

[ortuno, 2015/07/15 23:00:46]

Should we add a histogram for this?

[Jeffrey Yasskin, 2015/07/17 01:32:44]

Will do, but not today. I'll ping Monday when it's done.

[Jeffrey Yasskin, 2015/07/21 00:47:05]

Done in https://codereview.chromium.org/1248573002.

+        << "Got a requestDevice IPC without a matching RenderFrameHost: "
+        << render_process_id_ << ", " << routing_id;
+    Send(new BluetoothMsg_RequestDeviceError(
+        thread_id, request_id, WebBluetoothError::RequestDeviceWithoutFrame));
+  }
+
   // TODO(scheib): Device selection UI: crbug.com/436280
   // TODO(scheib): Utilize BluetoothAdapter::Observer::DeviceAdded/Removed.
   if (adapter_.get()) {
     if (!request_device_sessions_
              .insert(std::make_pair(
                  std::make_pair(thread_id, request_id),
-                 RequestDeviceSession(filters, optional_services)))
+                 RequestDeviceSession(routing_id, filters, optional_services)))
              .second) {
       LOG(ERROR) << "2 requestDevice() calls with the same thread_id ("
                  << thread_id << ") and request_id (" << request_id