Implementation of 'AudioContext.getOutputTimestamp' method

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

Index: third_party/WebKit/Source/modules/webaudio/AbstractAudioContext.cpp
diff --git a/third_party/WebKit/Source/modules/webaudio/AbstractAudioContext.cpp b/third_party/WebKit/Source/modules/webaudio/AbstractAudioContext.cpp
index 36344db0f2263eac94c7836d70103eac6972a9b6..12a663d46470477573285b1ae3e9472f89c1b96b 100644
--- a/third_party/WebKit/Source/modules/webaudio/AbstractAudioContext.cpp
+++ b/third_party/WebKit/Source/modules/webaudio/AbstractAudioContext.cpp
@@ -32,8 +32,11 @@
 #include "core/dom/Document.h"
 #include "core/dom/ExceptionCode.h"
 #include "core/dom/ExecutionContextTask.h"
+#include "core/frame/LocalDOMWindow.h"
 #include "core/frame/Settings.h"
 #include "core/html/HTMLMediaElement.h"
+#include "core/timing/DOMWindowPerformance.h"
+#include "core/timing/Performance.h"
 #include "modules/mediastream/MediaStream.h"
 #include "modules/webaudio/AnalyserNode.h"
 #include "modules/webaudio/AudioBuffer.h"
@@ -43,6 +46,7 @@
 #include "modules/webaudio/AudioListener.h"
 #include "modules/webaudio/AudioNodeInput.h"
 #include "modules/webaudio/AudioNodeOutput.h"
+#include "modules/webaudio/AudioTimestamp.h"
 #include "modules/webaudio/BiquadFilterNode.h"
 #include "modules/webaudio/ChannelMergerNode.h"
 #include "modules/webaudio/ChannelSplitterNode.h"
@@ -560,6 +564,30 @@ void AbstractAudioContext::recordUserGestureState()
     m_userGestureRequired = false;
 }
 
+static double toPerformanceTime(ExecutionContext* context, double seconds)
+{
+    LocalDOMWindow* window = context ? context->executingWindow() : nullptr;

[Raymond Toy, 2016/06/14 16:42:40]

Why not just early return with 0.0 if the context doesn't exist? Similarly if
the window doesn't exist.

[Mikhail, 2016/06/17 09:36:57]

Done.

+    Performance* performance = window ? DOMWindowPerformance::performance(*window) : nullptr;
+    return performance ? performance->monotonicTimeToDOMHighResTimeStamp(seconds) : 0.0;
+}
+
+void AbstractAudioContext::getOutputTimestamp(AudioTimestamp& result)
+{
+    if (!m_destinationNode) {
+        result.setContextTime(0.0);
+        result.setPerformanceTime(0.0);
+        return;
+    }
+    AudioDestinationHandler& destinationHandler = m_destinationNode->audioDestinationHandler();
+
+    WebAudioTimestamp outputTimestamp = destinationHandler.outputTimestamp();
+    double contextTime = outputTimestamp.frames / static_cast<double>(destinationHandler.sampleRate());
+    double performanceTime = outputTimestamp.seconds ? toPerformanceTime(getExecutionContext(), outputTimestamp.seconds) : 0.0;
+
+    result.setContextTime(contextTime);
+    result.setPerformanceTime(performanceTime);
+}
+
 String AbstractAudioContext::state() const
 {
     // These strings had better match the strings for AudioContextState in AudioContext.idl.