Revert of Remove SK_SUPPORT_LEGACY_DEEPFLATTENING.

src/effects/SkBlurImageFilter.cpp

Index: src/effects/SkBlurImageFilter.cpp
diff --git a/src/effects/SkBlurImageFilter.cpp b/src/effects/SkBlurImageFilter.cpp
index e5bb8c1e74592ef7db9a5e77ae5341d73bf6f644..4166d200355632e6ef8374ac4eb018e7460519a8 100644
--- a/src/effects/SkBlurImageFilter.cpp
+++ b/src/effects/SkBlurImageFilter.cpp
@@ -30,6 +30,18 @@
     sigma.fY = SkMinScalar(SkScalarAbs(sigma.fY), MAX_SIGMA);
     return sigma;
 }
+
+#ifdef SK_SUPPORT_LEGACY_DEEPFLATTENING
+SkBlurImageFilter::SkBlurImageFilter(SkReadBuffer& buffer)
+  : INHERITED(1, buffer) {
+    fSigma.fWidth = buffer.readScalar();
+    fSigma.fHeight = buffer.readScalar();
+    buffer.validate(SkScalarIsFinite(fSigma.fWidth) &&
+                    SkScalarIsFinite(fSigma.fHeight) &&
+                    (fSigma.fWidth >= 0) &&
+                    (fSigma.fHeight >= 0));
+}
+#endif
 
 SkBlurImageFilter::SkBlurImageFilter(SkScalar sigmaX,
                                      SkScalar sigmaY,