Move handle of HRTFDatabaseLoader to AudioListener.

Fix regression on specific application.

http://googlechrome.github.io/web-audio-samples/samples/audio/box2d-js/box2d-audio.html

Although a HRTFDatabaseLoader should keep the handle until AudioContext is destroyed,
a panner node tries to create the loader again since being removed the handle
by deref() of AudioNode.

The handle has been moved to AudioListener that is related mostly to keep the handle.

BUG=393751

Review URL: https://codereview.chromium.org/393363002

git-svn-id: svn://svn.chromium.org/blink/trunk@178583 bbb929c8-8fbe-4397-9dbb-9b2b20218538

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

@@ -34,6 +34,7 @@
 
 #include "modules/webaudio/PannerNode.h"
 #include "platform/audio/AudioBus.h"
+#include "platform/audio/HRTFDatabaseLoader.h"
 
 namespace blink {
 
@@ -71,6 +72,22 @@ void AudioListener::removePanner(PannerNode* panner)
     }
 }
 
+void AudioListener::createAndLoadHRTFDatabaseLoader(float sampleRate)
+{
+    if (!m_hrtfDatabaseLoader)
+        m_hrtfDatabaseLoader = HRTFDatabaseLoader::createAndLoadAsynchronouslyIfNecessary(sampleRate);
+}
+
+bool AudioListener::isHRTFDatabaseLoaded()
+{
+    return m_hrtfDatabaseLoader->isLoaded();
+}
+
+void AudioListener::waitForHRTFDatabaseLoaderThreadCompletion()
+{
+    m_hrtfDatabaseLoader->waitForLoaderThreadCompletion();
+}
+
 void AudioListener::markPannersAsDirty(unsigned type)
 {
     for (unsigned i = 0; i < m_panners.size(); ++i)

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

@@ -38,6 +38,7 @@
 
 namespace blink {
 
+class HRTFDatabaseLoader;
 class PannerNode;
 
 // AudioListener maintains the state of the listener in the audio scene as defined in the OpenAL specification.
@@ -79,6 +80,12 @@ public:
     void addPanner(PannerNode*);
     void removePanner(PannerNode*);
 
+    // HRTF DB loader
+    HRTFDatabaseLoader* hrtfDatabaseLoader() { return m_hrtfDatabaseLoader.get(); }
+    void createAndLoadHRTFDatabaseLoader(float);
+    bool isHRTFDatabaseLoaded();
+    void waitForHRTFDatabaseLoaderThreadCompletion();
+
     void trace(Visitor*) { }
 
 private:
@@ -100,9 +107,10 @@ private:
 
     // Synchronize a panner's process() with setting of the state of the listener.
     mutable Mutex m_listenerLock;
-
     // List for pannerNodes in context.
     Vector<PannerNode*> m_panners;
+    // HRTF DB loader for panner node.
+    RefPtr<HRTFDatabaseLoader> m_hrtfDatabaseLoader;
 };
 
 } // WebCore

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

@@ -63,7 +63,7 @@ PannerNode::PannerNode(AudioContext* context, float sampleRate)
 {
     // Load the HRTF database asynchronously so we don't block the Javascript thread while creating the HRTF database.
     // The HRTF panner will return zeroes until the database is loaded.
-    m_hrtfDatabaseLoader = HRTFDatabaseLoader::createAndLoadAsynchronouslyIfNecessary(context->sampleRate());
+    listener()->createAndLoadHRTFDatabaseLoader(context->sampleRate());
 
     ScriptWrappable::init(this);
     addInput();
@@ -123,9 +123,9 @@ void PannerNode::process(size_t framesToProcess)
 
     if (tryLocker.locked() && tryListenerLocker.locked()) {
         // HRTFDatabase should be loaded before proceeding for offline audio context when the panning model is HRTF.
-        if (m_panningModel == Panner::PanningModelHRTF && !m_hrtfDatabaseLoader->isLoaded()) {
+        if (m_panningModel == Panner::PanningModelHRTF && !listener()->isHRTFDatabaseLoaded()) {
             if (context()->isOfflineContext()) {
-                m_hrtfDatabaseLoader->waitForLoaderThreadCompletion();
+                listener()->waitForHRTFDatabaseLoaderThreadCompletion();
             } else {
                 destination->zero();
                 return;
@@ -160,7 +160,7 @@ void PannerNode::initialize()
     if (isInitialized())
         return;
 
-    m_panner = Panner::create(m_panningModel, sampleRate(), m_hrtfDatabaseLoader.get());
+    m_panner = Panner::create(m_panningModel, sampleRate(), listener()->hrtfDatabaseLoader());
     listener()->addPanner(this);
 
     AudioNode::initialize();
@@ -211,7 +211,7 @@ bool PannerNode::setPanningModel(unsigned model)
         if (!m_panner.get() || model != m_panningModel) {
             // This synchronizes with process().
             MutexLocker processLocker(m_processLock);
-            OwnPtr<Panner> newPanner = Panner::create(model, sampleRate(), m_hrtfDatabaseLoader.get());
+            OwnPtr<Panner> newPanner = Panner::create(model, sampleRate(), listener()->hrtfDatabaseLoader());
             m_panner = newPanner.release();
             m_panningModel = model;
         }

third_party/WebKit/Source/modules/webaudio/PannerNode.h

@@ -28,7 +28,6 @@
 #include "platform/audio/AudioBus.h"
 #include "platform/audio/Cone.h"
 #include "platform/audio/Distance.h"
-#include "platform/audio/HRTFDatabaseLoader.h"
 #include "platform/audio/Panner.h"
 #include "modules/webaudio/AudioListener.h"
 #include "modules/webaudio/AudioNode.h"
@@ -155,8 +154,6 @@ private:
     float m_cachedDistanceConeGain;
     double m_cachedDopplerRate;
 
-    RefPtr<HRTFDatabaseLoader> m_hrtfDatabaseLoader;
-
     // AudioContext's connection count
     unsigned m_connectionCount;