Simplify flattening to just write enough to call the factory

src/effects/SkMatrixImageFilter.cpp

Index: src/effects/SkMatrixImageFilter.cpp
diff --git a/src/effects/SkMatrixImageFilter.cpp b/src/effects/SkMatrixImageFilter.cpp
index c7c815a761dec37b3acb782bba71220ee4a69352..5b234a686e584764ee36e4e8ca636b30e78cc99d 100644
--- a/src/effects/SkMatrixImageFilter.cpp
+++ b/src/effects/SkMatrixImageFilter.cpp
@@ -29,14 +29,27 @@ SkMatrixImageFilter* SkMatrixImageFilter::Create(const SkMatrix& transform,
     return SkNEW_ARGS(SkMatrixImageFilter, (transform, filterLevel, input));
 }
 
+#ifdef SK_SUPPORT_LEGACY_DEEPFLATTENING
 SkMatrixImageFilter::SkMatrixImageFilter(SkReadBuffer& buffer)
   : INHERITED(1, buffer) {
     buffer.readMatrix(&fTransform);
     fFilterLevel = static_cast<SkPaint::FilterLevel>(buffer.readInt());
 }
+#endif
+
+SkFlattenable* SkMatrixImageFilter::CreateProc(SkReadBuffer& buffer) {
+    Common common;
+    if (!common.unflatten(buffer, 1)) {
+        return NULL;
+    }
+    SkMatrix matrix;
+    buffer.readMatrix(&matrix);
+    SkPaint::FilterLevel level = static_cast<SkPaint::FilterLevel>(buffer.readInt());
+    return Create(matrix, level, common.inputAt(0));
+}
 
 void SkMatrixImageFilter::flatten(SkWriteBuffer& buffer) const {
-    this->INHERITED::flatten(buffer);
+    this->flattenCommon(buffer);
     buffer.writeMatrix(fTransform);
     buffer.writeInt(fFilterLevel);
 }