Support for AudioContextOptions latencyHint.

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

Index: third_party/WebKit/Source/modules/webaudio/AudioContext.cpp
diff --git a/third_party/WebKit/Source/modules/webaudio/AudioContext.cpp b/third_party/WebKit/Source/modules/webaudio/AudioContext.cpp
index 3628954ddd8a663df1dbe95eec51cbc74a465e2a..e71b37d8df9c79727cbc063548293b95c4823a87 100644
--- a/third_party/WebKit/Source/modules/webaudio/AudioContext.cpp
+++ b/third_party/WebKit/Source/modules/webaudio/AudioContext.cpp
@@ -14,9 +14,12 @@
 #include "core/timing/DOMWindowPerformance.h"
 #include "core/timing/Performance.h"
 #include "modules/webaudio/AudioBufferCallback.h"
+#include "modules/webaudio/AudioContextOptions.h"
 #include "modules/webaudio/AudioTimestamp.h"
+#include "modules/webaudio/DefaultAudioDestinationNode.h"
 #include "platform/Histogram.h"
 #include "platform/audio/AudioUtilities.h"
+#include "public/platform/WebAudioLatencyHint.h"
 
 #if DEBUG_AUDIONODE_REFERENCES
 #include <stdio.h>
@@ -31,6 +34,7 @@ static unsigned s_hardwareContextCount = 0;
 static unsigned s_contextId = 0;
 
 AudioContext* AudioContext::create(Document& document,
+                                   const AudioContextOptions& contextOptions,
                                    ExceptionState& exceptionState) {
   DCHECK(isMainThread());
 
@@ -45,7 +49,14 @@ AudioContext* AudioContext::create(Document& document,
     return nullptr;
   }
 
-  AudioContext* audioContext = new AudioContext(document);
+  WebAudioLatencyHint latencyHint(WebAudioLatencyHint::kCategoryInteractive);
+  if (contextOptions.latencyHint().isAudioContextLatencyCategory()) {
+    latencyHint = WebAudioLatencyHint(
+        contextOptions.latencyHint().getAsAudioContextLatencyCategory());
+  }
+  // TODO: add support for latencyHint().isDouble()
+
+  AudioContext* audioContext = new AudioContext(document, latencyHint);
   audioContext->suspendIfNeeded();
 
   if (!AudioUtilities::isValidAudioBufferSampleRate(
@@ -87,8 +98,12 @@ AudioContext* AudioContext::create(Document& document,
   return audioContext;
 }
 
-AudioContext::AudioContext(Document& document)
-    : BaseAudioContext(&document), m_contextId(s_contextId++) {}
+AudioContext::AudioContext(Document& document,
+                           const WebAudioLatencyHint& latencyHint)
+    : BaseAudioContext(&document), m_contextId(s_contextId++) {
+  m_destinationNode = DefaultAudioDestinationNode::create(this, latencyHint);
+  initialize();
+}
 
 AudioContext::~AudioContext() {
 #if DEBUG_AUDIONODE_REFERENCES
@@ -236,4 +251,8 @@ void AudioContext::stopRendering() {
   }
 }
 
+double AudioContext::baseLatency() const {
+  return framesPerBuffer() * 2 / static_cast<double>(sampleRate());
+}
+
 }  // namespace blink