Support for AudioContextOptions latencyHint.

third_party/WebKit/Source/modules/webaudio/AudioContext.h

Index: third_party/WebKit/Source/modules/webaudio/AudioContext.h
diff --git a/third_party/WebKit/Source/modules/webaudio/AudioContext.h b/third_party/WebKit/Source/modules/webaudio/AudioContext.h
index 9187b569422e2ad46d911718852862627a46aa74..fa2f32a199420e8a896ec8dc2014f1e6435ce701 100644
--- a/third_party/WebKit/Source/modules/webaudio/AudioContext.h
+++ b/third_party/WebKit/Source/modules/webaudio/AudioContext.h
@@ -7,6 +7,7 @@
 
 #include "bindings/core/v8/ScriptPromise.h"
 #include "bindings/core/v8/ScriptPromiseResolver.h"
+#include "modules/webaudio/AudioContextOptions.h"
 #include "modules/webaudio/BaseAudioContext.h"
 #include "platform/heap/Handle.h"
 
@@ -18,11 +19,16 @@ class ScriptState;
 
 // This is an BaseAudioContext which actually plays sound, unlike an
 // OfflineAudioContext which renders sound into a buffer.
-class AudioContext : public BaseAudioContext {
+class MODULES_EXPORT AudioContext : public BaseAudioContext {
   DEFINE_WRAPPERTYPEINFO();
 
  public:
-  static AudioContext* create(Document&, ExceptionState&);
+  static AudioContext* create(Document&,
+                              const AudioContextOptions&,
+                              ExceptionState&);
+  static AudioContext* create(Document&,
+                              const WebAudioLatencyHint&,
+                              ExceptionState&);

[hongchan, 2016/12/02 17:40:11]

This is slightly confusing. Why do we need two different static creators? Isn't
the latency hint a part of the context options?
Please do make comments why we need 2 different creators - but preferably this
needs to be refactored into one.

[Andrew MacPherson, 2016/12/05 14:12:53]

Makes sense, I have refactored this down to 1 static constructor now. The second
one was being used by the BaseAudioContext::create() method which only appears
to be used in the BaseAudioContextTest.

 
   ~AudioContext() override;
   DECLARE_VIRTUAL_TRACE();
@@ -35,8 +41,10 @@ class AudioContext : public BaseAudioContext {
 
   bool hasRealtimeConstraint() final { return true; }
 
+  double baseLatency() const;
+
  protected:
-  AudioContext(Document&);
+  AudioContext(Document&, const WebAudioLatencyHint&);
 
   void didClose() final;