Report PeriodicWave memory usage to v8 so GC can be properly scheduled

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

Index: third_party/WebKit/Source/modules/webaudio/PeriodicWave.h
diff --git a/third_party/WebKit/Source/modules/webaudio/PeriodicWave.h b/third_party/WebKit/Source/modules/webaudio/PeriodicWave.h
index 2d764fa5b55c055c47730ec5ec115e15c367f02a..0fb51be5ebce1e2a85ec5df92b9a2f2e69929739 100644
--- a/third_party/WebKit/Source/modules/webaudio/PeriodicWave.h
+++ b/third_party/WebKit/Source/modules/webaudio/PeriodicWave.h
@@ -48,6 +48,8 @@ public:
     // Creates an arbitrary periodic wave given the frequency components (Fourier coefficients).
     static PeriodicWave* create(float sampleRate, DOMFloat32Array* real, DOMFloat32Array* imag, bool normalize);
 
+    virtual ~PeriodicWave();
+
     // Returns pointers to the lower and higher wave data for the pitch range containing
     // the given fundamental frequency. These two tables are in adjacent "pitch" ranges
     // where the higher table will have the maximum number of partials which won't alias when played back
@@ -72,6 +74,8 @@ private:
 
     void generateBasicWaveform(int);
 
+    size_t m_v8ExternalMemory;
+
     float m_sampleRate;
     unsigned m_numberOfRanges;
     float m_centsPerRange;
@@ -88,6 +92,8 @@ private:
 
     unsigned numberOfPartialsForRange(unsigned rangeIndex) const;
 
+    void adjustV8ExternalMemory(int delta);
+
     // Creates tables based on numberOfComponents Fourier coefficients.
     void createBandLimitedTables(const float* real, const float* imag, unsigned numberOfComponents, bool disableNormalization);
     Vector<OwnPtr<AudioFloatArray>> m_bandLimitedTables;