Revert a behavioral change in AudioManagerWin::GetInputStreamParameters.

media/audio/win/audio_manager_win.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 "media/audio/win/audio_manager_win.h"
 
 #include <windows.h>
 #include <objbase.h>  // This has to be before initguid.h
 #include <initguid.h>
 #include <mmsystem.h>
@@ skipping 267 matching lines @@
 
 AudioParameters AudioManagerWin::GetInputStreamParameters(
     const std::string& device_id) {
   AudioParameters parameters;
   HRESULT hr =
       CoreAudioUtil::GetPreferredAudioParameters(device_id, false, &parameters);
 
   if (FAILED(hr) || !parameters.IsValid()) {
     LOG(WARNING) << "Unable to get preferred audio params for " << device_id
                  << " 0x" << std::hex << hr;
-    return parameters;
+    // TODO(tommi): We appear to have callers to GetInputStreamParameters that
+    // rely on getting valid audio parameters returned for an invalid or
+    // unavailable device. We should track down those code paths (it is likely
+    // that they actually don't need a real device but depend on the audio
+    // code path somehow for a configuration - e.g. tab capture).
+    parameters =
+        AudioParameters(AudioParameters::AUDIO_PCM_LINEAR,
+                        CHANNEL_LAYOUT_STEREO, 48000, 16, kFallbackBufferSize);
   }
 
   int user_buffer_size = GetUserBufferSize();
   if (user_buffer_size)
     parameters.set_frames_per_buffer(user_buffer_size);
 
   return parameters;
 }
 
 std::string AudioManagerWin::GetAssociatedOutputDeviceID(
@@ skipping 161 matching lines @@
 ScopedAudioManagerPtr CreateAudioManager(
     scoped_refptr<base::SingleThreadTaskRunner> task_runner,
     scoped_refptr<base::SingleThreadTaskRunner> worker_task_runner,
     AudioLogFactory* audio_log_factory) {
   return ScopedAudioManagerPtr(
       new AudioManagerWin(std::move(task_runner), std::move(worker_task_runner),
                           audio_log_factory));
 }
 
 }  // namespace media