Ensure group ID is different for devices which are not associated.

content/renderer/media/user_media_client_impl.cc

 // Copyright (c) 2012 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.
 
 #include "content/renderer/media/user_media_client_impl.h"
 
 #include <stddef.h>
 
 #include <utility>
 #include <vector>
@@ skipping 460 matching lines @@
   // as the group id for input and output audio devices. If an input device
   // doesn't have an associated output device, we use the input device's own id.
   // We don't support group id for video devices, that's left empty.
   blink::WebVector<blink::WebMediaDeviceInfo>
       devices(request->audio_input_devices.size() +
               request->video_input_devices.size() +
               request->audio_output_devices.size());
   for (size_t i = 0; i  < request->audio_input_devices.size(); ++i) {
     const MediaStreamDevice& device = request->audio_input_devices[i].device;
     DCHECK_EQ(device.type, MEDIA_DEVICE_AUDIO_CAPTURE);
+
+    // We add an arbitrary character to the device ID in order to avoid the same
+    // group ID for the input and output devices that share the same ID but are
+    // not in the same physical device. This may happen with the default and
+    // communication devices.
     std::string group_id = base::UintToString(base::Hash(
-        !device.matched_output_device_id.empty() ?
-            device.matched_output_device_id :
-            device.id));
+        device.matched_output_device_id.empty() ?
+            device.id + "i" :
+            device.matched_output_device_id));
     devices[i].initialize(
         blink::WebString::fromUTF8(device.id),
         blink::WebMediaDeviceInfo::MediaDeviceKindAudioInput,
         blink::WebString::fromUTF8(device.name),
         blink::WebString::fromUTF8(group_id));
   }
   size_t offset = request->audio_input_devices.size();
   for (size_t i = 0; i  < request->video_input_devices.size(); ++i) {
     const MediaStreamDevice& device = request->video_input_devices[i].device;
     DCHECK_EQ(device.type, MEDIA_DEVICE_VIDEO_CAPTURE);
@@ skipping 699 matching lines @@
 
 bool UserMediaClientImpl::UserMediaRequestInfo::HasPendingSources() const {
   return !sources_waiting_for_callback_.empty();
 }
 
 void UserMediaClientImpl::OnDestruct() {
   delete this;
 }
 
 }  // namespace content