Fix WebAudio support for discrete channel layouts.

content/renderer/renderer_blink_platform_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_blink_platform_impl.h"
 
 #include <memory>
 #include <utility>
 
 #include "base/command_line.h"
@@ skipping 657 matching lines @@
     const blink::WebSecurityOrigin& security_origin) {
   // Use a mock for testing.
   blink::WebAudioDevice* mock_device =
       GetContentClient()->renderer()->OverrideCreateAudioDevice();
   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.
-  media::ChannelLayout layout = media::CHANNEL_LAYOUT_UNSUPPORTED;
-  switch (channels) {
-    case 1:
-      layout = media::CHANNEL_LAYOUT_MONO;
-      break;
-    case 2:
-      layout = media::CHANNEL_LAYOUT_STEREO;
-      break;
-    case 3:
-      layout = media::CHANNEL_LAYOUT_2_1;

[DaleCurtis, 2017/02/21 22:22:44]

New code will return SURROUND here:

Old: Front L, Front R, Back C
New: Front L, Front R, Front C

-      break;
-    case 4:
-      layout = media::CHANNEL_LAYOUT_4_0;

[DaleCurtis, 2017/02/21 22:22:44]

New code will return QUAD here:

Old: Front L, Front R, Front C, Back C
New: Front L, Front R, Back L, Back R

-      break;
-    case 5:
-      layout = media::CHANNEL_LAYOUT_5_0;
-      break;
-    case 6:
-      layout = media::CHANNEL_LAYOUT_5_1;
-      break;
-    case 7:
-      layout = media::CHANNEL_LAYOUT_7_0;

[DaleCurtis, 2017/02/21 22:22:44]

New code will return 6.1 here:

Old: Front L, Front R, Front C, Side L, Side R, Front LofC, Front RofC
New: Front L, Front R, Front C, LFE, Side L, Side R, Rear Center

-      break;
-    case 8:
-      layout = media::CHANNEL_LAYOUT_7_1;
-      break;
-    default:
-      // TODO need to also pass 'channels' into RendererWebAudioDeviceImpl for
-      // CHANNEL_LAYOUT_DISCRETE
-      NOTREACHED();
-  }
+  media::ChannelLayout layout = media::GuessChannelLayout(channels);
+  if (layout == media::CHANNEL_LAYOUT_UNSUPPORTED)
+    layout = media::CHANNEL_LAYOUT_DISCRETE;
 
-  int session_id = 0;
+  int session_id;
   if (input_device_id.isNull() ||
       !base::StringToInt(input_device_id.utf8(), &session_id)) {

[DaleCurtis, 2017/02/21 22:22:44]

Note: This method may write to |session_id| even when failing, so the old path
was incorrect. It needs to clear session_id if the conversion fails.
|input_channels| is not used and I don't think the DLOG was adding anything, so
removed too.

-    if (input_channels > 0)
-      DLOG(WARNING) << "createAudioDevice(): request for audio input ignored";
-
-    input_channels = 0;
+    session_id = 0;
   }
 
   return RendererWebAudioDeviceImpl::Create(
-      layout, latency_hint, callback, session_id,
+      layout, channels, latency_hint, callback, session_id,
       static_cast<url::Origin>(security_origin));
 }
 
 bool RendererBlinkPlatformImpl::loadAudioResource(
     blink::WebAudioBus* destination_bus,
     const char* audio_file_data,
     size_t data_size) {
   return DecodeAudioFileData(
       destination_bus, audio_file_data, data_size);
 }
@@ skipping 563 matching lines @@
 //------------------------------------------------------------------------------
 void RendererBlinkPlatformImpl::requestPurgeMemory() {
   // TODO(tasak|bashi): We should use ChildMemoryCoordinator here, but
   // ChildMemoryCoordinator isn't always available as it's only initialized
   // when kMemoryCoordinatorV0 is enabled.
   // Use ChildMemoryCoordinator when memory coordinator is always enabled.
   base::MemoryCoordinatorClientRegistry::GetInstance()->PurgeMemory();
 }
 
 }  // namespace content