Simplify flattening to just write enough to call the factory

src/effects/SkComposeImageFilter.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBitmap.h"
 #include "SkComposeImageFilter.h"
 #include "SkReadBuffer.h"
 #include "SkWriteBuffer.h"
 
 SkComposeImageFilter::~SkComposeImageFilter() {
 }
 
 bool SkComposeImageFilter::onFilterImage(Proxy* proxy,
                                          const SkBitmap& src,
                                          const Context& ctx,
                                          SkBitmap* result,
                                          SkIPoint* offset) const {
     SkImageFilter* outer = getInput(0);
     SkImageFilter* inner = getInput(1);
 
-    if (!outer && !inner) {
-        return false;
-    }
-
-    if (!outer || !inner) {
-        return (outer ? outer : inner)->filterImage(proxy, src, ctx, result, offset);
-    }
-
     SkBitmap tmp;
     return inner->filterImage(proxy, src, ctx, &tmp, offset) &&
            outer->filterImage(proxy, tmp, ctx, result, offset);
 }
 
 bool SkComposeImageFilter::onFilterBounds(const SkIRect& src,
                                           const SkMatrix& ctm,
                                           SkIRect* dst) const {
     SkImageFilter* outer = getInput(0);
     SkImageFilter* inner = getInput(1);
 
-    if (!outer && !inner) {
-        return false;
-    }
-
-    if (!outer || !inner) {
-        return (outer ? outer : inner)->filterBounds(src, ctm, dst);
-    }
-
     SkIRect tmp;
-    return inner->filterBounds(src, ctm, &tmp) &&
-           outer->filterBounds(tmp, ctm, dst);
+    return inner->filterBounds(src, ctm, &tmp) && outer->filterBounds(tmp, ctm, dst);
 }
 
+SkFlattenable* SkComposeImageFilter::CreateProc(SkReadBuffer& buffer) {
+    SK_IMAGEFILTER_UNFLATTEN_COMMON(common, 2);
+    return SkComposeImageFilter::Create(common.getInput(0), common.getInput(1));
+}
+
+#ifdef SK_SUPPORT_LEGACY_DEEPFLATTENING
 SkComposeImageFilter::SkComposeImageFilter(SkReadBuffer& buffer)
   : INHERITED(2, buffer) {
 }
+#endif