Load HRTF database only when the panner is set to HRTF

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

Index: third_party/WebKit/Source/modules/webaudio/AudioListener.cpp
diff --git a/third_party/WebKit/Source/modules/webaudio/AudioListener.cpp b/third_party/WebKit/Source/modules/webaudio/AudioListener.cpp
index dacfa906e23e645496492f441e4f121c5fa8cf77..eea7d72d7c566e9e47945147022957923c2acd43 100644
--- a/third_party/WebKit/Source/modules/webaudio/AudioListener.cpp
+++ b/third_party/WebKit/Source/modules/webaudio/AudioListener.cpp
@@ -231,13 +231,15 @@ void AudioListener::updateState()
 
 void AudioListener::createAndLoadHRTFDatabaseLoader(float sampleRate)
 {
+    DCHECK(isMainThread());
+
     if (!m_hrtfDatabaseLoader)
         m_hrtfDatabaseLoader = HRTFDatabaseLoader::createAndLoadAsynchronouslyIfNecessary(sampleRate);
 }
 
 bool AudioListener::isHRTFDatabaseLoaded()
 {
-    return m_hrtfDatabaseLoader->isLoaded();
+    return m_hrtfDatabaseLoader && m_hrtfDatabaseLoader->isLoaded();
 }
 
 void AudioListener::waitForHRTFDatabaseLoaderThreadCompletion()