bug 1388656 keep response buffer on graph thread only long enough to initialize the Reverb r=padenot

MozReview-Commit-ID: 6DvpXeWPGHp

--HG--
extra : rebase_source : 50a2f7e4df207d971894189d9de8844fab0a7954

dom/media/webaudio/ConvolverNode.cpp

@@ -49,7 +49,6 @@ public:
     case BUFFER_LENGTH:
       // BUFFER_LENGTH is the first parameter that we set when setting a new buffer,
       // so we should be careful to invalidate the rest of our state here.
-      mBuffer = nullptr;
       mSampleRate = 0.0f;
       mBufferLength = aParam;
       mLeftOverData = INT32_MIN;
@@ -75,7 +74,7 @@ public:
   }
   void SetBuffer(already_AddRefed<ThreadSharedFloatArrayBufferList> aBuffer) override
   {
-    mBuffer = aBuffer;
+    RefPtr<ThreadSharedFloatArrayBufferList> buffer = aBuffer;
 
     // Note about empirical tuning (this is copied from Blink)
     // The maximum FFT size affects reverb performance and accuracy.
@@ -85,13 +84,13 @@ public:
     // Very large FFTs will have worse phase errors. Given these constraints 32768 is a good compromise.
     const size_t MaxFFTSize = 32768;
 
-    if (!mBuffer || !mBufferLength || !mSampleRate) {
+    if (!buffer || !mBufferLength || !mSampleRate) {
       mReverb = nullptr;
       mLeftOverData = INT32_MIN;
       return;
     }
 
-    mReverb = new WebCore::Reverb(mBuffer, mBufferLength,
+    mReverb = new WebCore::Reverb(buffer, mBufferLength,
                                   MaxFFTSize, mUseBackgroundThreads,
                                   mNormalize, mSampleRate);
   }
@@ -159,9 +158,6 @@ public:
   size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const override
   {
     size_t amount = AudioNodeEngine::SizeOfExcludingThis(aMallocSizeOf);
-    if (mBuffer && !mBuffer->IsShared()) {
-      amount += mBuffer->SizeOfIncludingThis(aMallocSizeOf);
-    }
 
     if (mReverb) {
       amount += mReverb->sizeOfIncludingThis(aMallocSizeOf);
@@ -176,7 +172,6 @@ public:
   }
 
 private:
-  RefPtr<ThreadSharedFloatArrayBufferList> mBuffer;
   nsAutoPtr<WebCore::Reverb> mReverb;
   int32_t mBufferLength;
   int32_t mLeftOverData;