bluetooth: Web Bluetooth can filter by empty device names, doesn't leak MACs.

content/browser/bluetooth/web_bluetooth_service_impl.cc

Index: content/browser/bluetooth/web_bluetooth_service_impl.cc
diff --git a/content/browser/bluetooth/web_bluetooth_service_impl.cc b/content/browser/bluetooth/web_bluetooth_service_impl.cc
index 355e344b471a234ced30d2860c79d9a83d9e6dbb..84a387fd6e714cbec096aba357acfe89e298789a 100644
--- a/content/browser/bluetooth/web_bluetooth_service_impl.cc
+++ b/content/browser/bluetooth/web_bluetooth_service_impl.cc
@@ -783,8 +783,8 @@ void WebBluetoothServiceImpl::OnGetDeviceSuccess(
   blink::mojom::WebBluetoothDevicePtr device_ptr =
       blink::mojom::WebBluetoothDevice::New();
   device_ptr->id = device_id_for_origin;
-  // TODO(615720): Use the upcoming GetName (was GetDeviceName).
-  device_ptr->name = base::UTF16ToUTF8(device->GetNameForDisplay());
+  if (device->GetName())
+    device_ptr->name = device->GetName().value();

[ortuno, 2016/07/21 17:42:29]

optional nit to save one line: device_ptr->name = device->GetName() ?
device->GetName().value() : nullptr;

Also now that this can be null we need to make sure the renderer side
(web_bluetooth_impl) handles it correctly. I see two options:

1. Keep web_bluetooth_impl.cc:192 as is. Meaning we rely on std::string::data to
be null terminated, which I'm not sure we can rely on[1], to produce a null
WebString.
2. Change web_bluetooth_impl.cc:192 to make it explicit that a null name returns
a null wtf::String e.g. device->name.is_null() ? blink::WebString() :
blink::WebString::fromUTF8(device->name).

[1] http://en.cppreference.com/w/cpp/string/basic_string/data

[scheib, 2016/07/30 02:38:14]

Changed to always assign -- to make the assignment clear, but required type
casting doesn't save the line.

Renderer also updated to correctly handle null.

[ortuno, 2016/07/31 18:00:05]

I'm surprised it requires type casting since the code before it directly passed
in a std::string.

   device_ptr->uuids = std::move(filtered_uuids);
 
   RecordRequestDeviceOutcome(UMARequestDeviceOutcome::SUCCESS);