Implement StereoPannerNode for robust stereo panning

Source/platform/audio/Spatializer.cpp

Index: Source/platform/audio/Spatializer.cpp
diff --git a/LICENSE b/Source/platform/audio/Spatializer.cpp
similarity index 71%
copy from LICENSE
copy to Source/platform/audio/Spatializer.cpp
index 70bcb8ad118978579fa055f7ecc99604930900ce..fe7996fea6ba77b53ddd9700f0c6443f92027e48 100644
--- a/LICENSE
+++ b/Source/platform/audio/Spatializer.cpp
@@ -1,8 +1,5 @@
 // Copyright 2014 The Chromium Authors. All rights reserved.
 //
-// The Chromium Authors can be found at
-// http://src.chromium.org/svn/trunk/src/AUTHORS
-//
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
@@ -28,3 +25,37 @@
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "config.h"
+
+#if ENABLE(WEB_AUDIO)
+
+#include "platform/audio/Spatializer.h"
+
+#include "platform/audio/StereoPanner.h"
+
+namespace blink {
+
+Spatializer* Spatializer::create(PanningModel model, float sampleRate)
+{
+    Spatializer* panner;
+
+    switch (model) {
+    case PanningModelEqualPower:
+        panner = new StereoPanner(sampleRate);
+        break;
+
+    // TODO: add the instantiation of BinauralPanner here.
+    // TODO: add the instantiation of SurroundPanner here.
+
+    default:
+        ASSERT_NOT_REACHED();
+        return nullptr;
+    }
+
+    return panner;
+}
+
+} // namespace blink
+
+#endif // ENABLE(WEB_AUDIO)