Bug 695498. Backout 7aa60d6408b3.

mDecoder can go NULL when we don't expect it.

image/src/RasterImage.cpp

@@ -2281,13 +2281,16 @@ RasterImage::WriteToDecoder(const char *aBuffer, PRUint32 aCount)
     curframe->UnlockImageData();
   }
 
-  nsresult status = mDecoder->GetDecoderError();
-  if (NS_SUCCEEDED(status)) {
-    // Keep track of the total number of bytes written over the lifetime of the
-    // decoder
-    mBytesDecoded += aCount;
-  }
-  return status;
+  if (!mDecoder)
+    return NS_ERROR_FAILURE;
+    
+  CONTAINER_ENSURE_SUCCESS(mDecoder->GetDecoderError());
+
+  // Keep track of the total number of bytes written over the lifetime of the
+  // decoder
+  mBytesDecoded += aCount;
+
+  return NS_OK;
 }
 
 // This function is called in situations where it's clear that we want the