Use a mock WebAudioDevice for layout tests

content/renderer/renderer_webkitplatformsupport_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/renderer_webkitplatformsupport_impl.h"
 
 #include "base/command_line.h"
 #include "base/files/file_path.h"
 #include "base/lazy_instance.h"
 #include "base/message_loop/message_loop_proxy.h"
@@ skipping 762 matching lines @@
 }
 
 WebAudioDevice*
 RendererWebKitPlatformSupportImpl::createAudioDevice(
     size_t buffer_size,
     unsigned input_channels,
     unsigned channels,
     double sample_rate,
     WebAudioDevice::RenderCallback* callback,
     const WebKit::WebString& input_device_id) {
+  // Use a mock for testing.
+  WebKit::WebAudioDevice* mock_device =
+      GetContentClient()->renderer()->OverrideCreateAudioDevice(sample_rate);
+  if (mock_device)
+    return mock_device;
+
   // The |channels| does not exactly identify the channel layout of the
   // device. The switch statement below assigns a best guess to the channel
   // layout based on number of channels.
   // TODO(crogers): WebKit should give the channel layout instead of the hard
   // channel count.
   media::ChannelLayout layout = media::CHANNEL_LAYOUT_UNSUPPORTED;
   switch (channels) {
     case 1:
       layout = media::CHANNEL_LAYOUT_MONO;
       break;
@@ skipping 257 matching lines @@
 
 //------------------------------------------------------------------------------
 
 WebKit::WebString RendererWebKitPlatformSupportImpl::convertIDNToUnicode(
     const WebKit::WebString& host,
     const WebKit::WebString& languages) {
   return net::IDNToUnicode(host.utf8(), languages.utf8());
 }
 
 }  // namespace content