Merge 157245 "Fix threading races on ConvolverNode::m_reverb in ..."

Source/modules/webaudio/ConvolverNode.cpp

Index: Source/modules/webaudio/ConvolverNode.cpp
===================================================================
--- Source/modules/webaudio/ConvolverNode.cpp	(revision 157689)
+++ Source/modules/webaudio/ConvolverNode.cpp	(working copy)
@@ -163,7 +163,12 @@
 
 double ConvolverNode::latencyTime() const
 {
-    return m_reverb ? m_reverb->latencyFrames() / static_cast<double>(sampleRate()) : 0;
+    MutexTryLocker tryLocker(m_processLock);
+    if (tryLocker.locked())
+        return m_reverb ? m_reverb->latencyFrames() / static_cast<double>(sampleRate()) : 0;
+    // Since we don't want to block the Audio Device thread, we return a large value
+    // instead of trying to acquire the lock.
+    return std::numeric_limits<double>::infinity();
 }
 
 } // namespace WebCore