Support for AudioContextOptions latencyHint.

third_party/WebKit/Source/modules/webaudio/BaseAudioContext.cpp

Index: third_party/WebKit/Source/modules/webaudio/BaseAudioContext.cpp
diff --git a/third_party/WebKit/Source/modules/webaudio/BaseAudioContext.cpp b/third_party/WebKit/Source/modules/webaudio/BaseAudioContext.cpp
index 020e539047db244fcc9878bc8f9e5da1fe0beefa..b34a84a473e027bad36087d0d30e2c775f8385c0 100644
--- a/third_party/WebKit/Source/modules/webaudio/BaseAudioContext.cpp
+++ b/third_party/WebKit/Source/modules/webaudio/BaseAudioContext.cpp
@@ -52,7 +52,6 @@
 #include "modules/webaudio/ChannelSplitterNode.h"
 #include "modules/webaudio/ConstantSourceNode.h"
 #include "modules/webaudio/ConvolverNode.h"
-#include "modules/webaudio/DefaultAudioDestinationNode.h"
 #include "modules/webaudio/DelayNode.h"
 #include "modules/webaudio/DynamicsCompressorNode.h"
 #include "modules/webaudio/GainNode.h"
@@ -79,9 +78,11 @@
 
 namespace blink {
 
-BaseAudioContext* BaseAudioContext::create(Document& document,
-                                           ExceptionState& exceptionState) {
-  return AudioContext::create(document, exceptionState);
+BaseAudioContext* BaseAudioContext::create(
+    Document& document,
+    const AudioContextOptions& contextOptions,
+    ExceptionState& exceptionState) {
+  return AudioContext::create(document, contextOptions, exceptionState);
 }
 
 // FIXME(dominicc): Devolve these constructors to AudioContext
@@ -111,10 +112,6 @@ BaseAudioContext::BaseAudioContext(Document* document)
     m_autoplayStatus = AutoplayStatus::AutoplayStatusFailed;
     m_userGestureRequired = true;
   }
-
-  m_destinationNode = DefaultAudioDestinationNode::create(this);
-
-  initialize();

[Raymond Toy, 2016/12/08 17:14:38]

Ah, nice catch.  You removed this because OfflineAudioContext was calling this
to create the context, which sets m_destinationNode here, but the
OfflineAudioContext would replace it with another right away.

Right?

[Andrew MacPherson, 2016/12/09 12:34:14]

The OfflineAudioContext actually uses a different constructor so it wasn't being
set here in that case, however now that the DefaultAudioDestinationNode takes a
WebAudioLatencyHint parameter I figured it would make sense to move these lines
into the AudioContext so that the BaseAudioContext doesn't need to know about
the WebAudioLatencyHint. This also made it so that both the OfflineAudioContext
and the AudioContext are now responsible for the m_destinationNode rather than
the BaseAudioContext creating it in one case only but not the other.

[Raymond Toy, 2016/12/13 15:53:11]

Thanks for the explanation.  This makes the code much nicer.

 }
 
 // Constructor for offline (non-realtime) rendering.