Support multiple HRTFDatabases for different sample-rates

Source/modules/webaudio/PannerNode.cpp

Index: Source/modules/webaudio/PannerNode.cpp
diff --git a/Source/modules/webaudio/PannerNode.cpp b/Source/modules/webaudio/PannerNode.cpp
index 147126b676dac9a2e04924b0f655dd9e90abf220..4845b32b64fd03c071afce64101e5e621fd4ea8c 100644
--- a/Source/modules/webaudio/PannerNode.cpp
+++ b/Source/modules/webaudio/PannerNode.cpp
@@ -144,8 +144,9 @@ void PannerNode::initialize()
 {
     if (isInitialized())
         return;
-        
-    m_panner = Panner::create(m_panningModel, sampleRate());
+
+    HRTFDatabase* database = context()->hrtfDatabaseLoader()->database();

[Ken Russell (switch to Gerrit), 2013/05/11 01:35:16]

There's a race condition in the fetching of the HRTFDatabase from the
HRTFDatabaseLoader. Since the HRTFDatabaseLoader creates the HRTFDatabase from
its database loader thread, there's a possibility that the database() method
call here will return NULL. To guard against this, it seems to me that the
Panner should probably take an HRTFDatabaseLoader as argument rather than an
HRTFDatabase. What do you think?

[Chris Rogers, 2013/05/13 20:05:22]

Good point, I'll switch this back to the previous behavior where the HRTFPanner
deals with the loader itself...

Fixed.

+    m_panner = Panner::create(m_panningModel, sampleRate(), database);
 
     AudioNode::initialize();
 }
@@ -199,8 +200,9 @@ bool PannerNode::setPanningModel(unsigned model)
         if (!m_panner.get() || model != m_panningModel) {
             // This synchronizes with process().
             MutexLocker processLocker(m_pannerLock);
-            
-            OwnPtr<Panner> newPanner = Panner::create(model, sampleRate());
+
+            HRTFDatabase* database = context()->hrtfDatabaseLoader()->database();
+            OwnPtr<Panner> newPanner = Panner::create(model, sampleRate(), database);
             m_panner = newPanner.release();
             m_panningModel = model;
         }