Sub-sample accurate start of OscillatorNode

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

Index: third_party/WebKit/Source/modules/webaudio/AudioScheduledSourceNode.cpp
diff --git a/third_party/WebKit/Source/modules/webaudio/AudioScheduledSourceNode.cpp b/third_party/WebKit/Source/modules/webaudio/AudioScheduledSourceNode.cpp
index 5146ef347543a9a8ace1d942f87fb98078f3d2f7..8dc1532e1e312ce9d2ad9408498803c7d91526b4 100644
--- a/third_party/WebKit/Source/modules/webaudio/AudioScheduledSourceNode.cpp
+++ b/third_party/WebKit/Source/modules/webaudio/AudioScheduledSourceNode.cpp
@@ -50,7 +50,8 @@ void AudioScheduledSourceHandler::updateSchedulingInfo(
     size_t quantumFrameSize,
     AudioBus* outputBus,
     size_t& quantumFrameOffset,
-    size_t& nonSilentFramesToProcess) {
+    size_t& nonSilentFramesToProcess,
+    double& startFrameOffset) {
   DCHECK(outputBus);
   if (!outputBus)
     return;
@@ -94,6 +95,10 @@ void AudioScheduledSourceHandler::updateSchedulingInfo(
     // Increment the active source count only if we're transitioning from
     // SCHEDULED_STATE to PLAYING_STATE.
     setPlaybackState(PLAYING_STATE);
+    // Determine the offset of the true start time from the starting frame.
+    startFrameOffset = m_startTime * sampleRate - startFrame;
+  } else {
+    startFrameOffset = 0;
   }
 
   quantumFrameOffset =