Revert of Remove SK_SUPPORT_LEGACY_DEEPFLATTENING.

src/effects/SkMergeImageFilter.cpp

Index: src/effects/SkMergeImageFilter.cpp
diff --git a/src/effects/SkMergeImageFilter.cpp b/src/effects/SkMergeImageFilter.cpp
index d932d3ccce50a05ffd5689cece10a926d3a16ada..9e7f4e543c743f9cc1afb5f98c30ece44cff8ab8 100755
--- a/src/effects/SkMergeImageFilter.cpp
+++ b/src/effects/SkMergeImageFilter.cpp
@@ -140,3 +140,24 @@
         buffer.writeByteArray(fModes, countInputs() * sizeof(fModes[0]));
     }
 }
+
+#ifdef SK_SUPPORT_LEGACY_DEEPFLATTENING
+SkMergeImageFilter::SkMergeImageFilter(SkReadBuffer& buffer)
+  : INHERITED(-1, buffer) {
+    bool hasModes = buffer.readBool();
+    if (hasModes) {
+        this->initAllocModes();
+        int nbInputs = countInputs();
+        size_t size = nbInputs * sizeof(fModes[0]);
+        SkASSERT(buffer.getArrayCount() == size);
+        if (buffer.validate(buffer.getArrayCount() == size) &&
+            buffer.readByteArray(fModes, size)) {
+            for (int i = 0; i < nbInputs; ++i) {
+                buffer.validate(SkIsValidMode((SkXfermode::Mode)fModes[i]));
+            }
+        }
+    } else {
+        fModes = 0;
+    }
+}
+#endif