Remove bogus DCHECK in content::UserMediaClientImpl and update unit test

content/renderer/media/user_media_client_impl_unittest.cc

Index: content/renderer/media/user_media_client_impl_unittest.cc
diff --git a/content/renderer/media/user_media_client_impl_unittest.cc b/content/renderer/media/user_media_client_impl_unittest.cc
index 500dea753caa7cad5e516b48833d811f7facdfb7..a0b5c294ef8c37a8a7128e63b2736cba34a4a192 100644
--- a/content/renderer/media/user_media_client_impl_unittest.cc
+++ b/content/renderer/media/user_media_client_impl_unittest.cc
@@ -264,6 +264,10 @@ class UserMediaClientImplTest : public ::testing::Test {
   }
 
   void FakeMediaStreamDispatcherRequestMediaDevicesComplete() {
+    // There may be repeated replies due to device or configuration changes.
+    used_media_impl_->OnDevicesEnumerated(
+        ms_dispatcher_->audio_input_request_id(),
+        ms_dispatcher_->audio_input_array());
     used_media_impl_->OnDevicesEnumerated(
         ms_dispatcher_->audio_input_request_id(),
         ms_dispatcher_->audio_input_array());
@@ -271,6 +275,12 @@ class UserMediaClientImplTest : public ::testing::Test {
         ms_dispatcher_->audio_output_request_id(),
         ms_dispatcher_->audio_output_array());
     used_media_impl_->OnDevicesEnumerated(
+        ms_dispatcher_->audio_output_request_id(),
+        ms_dispatcher_->audio_output_array());
+    used_media_impl_->OnDevicesEnumerated(
+        ms_dispatcher_->video_request_id(),
+        ms_dispatcher_->video_array());
+    used_media_impl_->OnDevicesEnumerated(
         ms_dispatcher_->video_request_id(),
         ms_dispatcher_->video_array());
   }