Enable Oilpan by default for webaudio/

Source/platform/audio/AudioDSPKernel.h

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 49 matching lines @@
     float sampleRate() const { return m_sampleRate; }
     double nyquist() const { return 0.5 * sampleRate(); }
 
     AudioDSPKernelProcessor* processor() { return m_kernelProcessor; }
     const AudioDSPKernelProcessor* processor() const { return m_kernelProcessor; }
 
     virtual double tailTime() const = 0;
     virtual double latencyTime() const = 0;
 
 protected:
+    // Oilpan: This raw pointer is safe because the AudioDSPKernelProcessor object is guaranteed

[tkent, 2014/08/15 07:39:01]

nit: I recommend to wrap code comments in 80 columns.

[haraken, 2014/08/15 08:08:00]

Done.

+    // to be kept alive while the AudioDSPKernel object is alive.
+    // Ideally we want to move the AudioDSPKernel hierarchy to the heap and use
+    // a Member<AudioDSPKernelProcessor>. However, we cannot do that because AudioDSPKernel can be
+    // allocated in audio threads (which are not registered to Oilpan).
+    GC_PLUGIN_IGNORE("")
     AudioDSPKernelProcessor* m_kernelProcessor;
     float m_sampleRate;
 };
 
 } // namespace blink
 
 #endif // AudioDSPKernel_h