Support for AudioContextOptions latencyHint.

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

Index: third_party/WebKit/Source/modules/webaudio/BaseAudioContext.h
diff --git a/third_party/WebKit/Source/modules/webaudio/BaseAudioContext.h b/third_party/WebKit/Source/modules/webaudio/BaseAudioContext.h
index 028ff3e9bb670b6388e9f3fdcf543aca528f0304..0a7fbcdc7d79bbca96a2adf63bc11a36e129d6ac 100644
--- a/third_party/WebKit/Source/modules/webaudio/BaseAudioContext.h
+++ b/third_party/WebKit/Source/modules/webaudio/BaseAudioContext.h
@@ -80,6 +80,7 @@ class ScriptState;
 class SecurityOrigin;
 class StereoPannerNode;
 class WaveShaperNode;
+class WebAudioLatencyHint;
 
 // BaseAudioContext is the cornerstone of the web audio API and all AudioNodes
 // are created from it.  For thread safety between the audio thread and the main
@@ -100,7 +101,9 @@ class MODULES_EXPORT BaseAudioContext : public EventTargetWithInlineData,
   enum AudioContextState { Suspended, Running, Closed };
 
   // Create an AudioContext for rendering to the audio hardware.
-  static BaseAudioContext* create(Document&, ExceptionState&);
+  static BaseAudioContext* create(Document&,
+                                  const WebAudioLatencyHint&,

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

BaseAudioContext neeeds |AudioContextOptions|. |AudioContextOptions| has the
latency hint in it. This signature does not reflect the structure.

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

Done.

+                                  ExceptionState&);
 
   ~BaseAudioContext() override;
 
@@ -137,7 +140,15 @@ class MODULES_EXPORT BaseAudioContext : public EventTargetWithInlineData,
   }
 
   float sampleRate() const {
-    return m_destinationNode ? m_destinationNode->handler().sampleRate() : 0;
+    return m_destinationNode
+               ? m_destinationNode->audioDestinationHandler().sampleRate()
+               : 0;
+  }
+
+  float framesPerBuffer() const {
+    return m_destinationNode
+               ? m_destinationNode->audioDestinationHandler().framesPerBuffer()
+               : 0;
   }
 
   String state() const;
@@ -305,7 +316,7 @@ class MODULES_EXPORT BaseAudioContext : public EventTargetWithInlineData,
   void maybeRecordStartAttempt();
 
  protected:
-  explicit BaseAudioContext(Document*);
+  explicit BaseAudioContext(Document*, const WebAudioLatencyHint&);
   BaseAudioContext(Document*,
                    unsigned numberOfChannels,
                    size_t numberOfFrames,