Outline SkImageFilter Make methods

src/effects/SkTestImageFilters.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkTestImageFilters.h"
 #include "SkCanvas.h"
 #include "SkReadBuffer.h"
 #include "SkSpecialImage.h"
 #include "SkSpecialSurface.h"
 #include "SkWriteBuffer.h"
 
 ///////////////////////////////////////////////////////////////////////////////
 
+sk_sp<SkImageFilter> SkDownSampleImageFilter::Make(SkScalar scale, sk_sp<SkImageFilter> input) {
+    if (!SkScalarIsFinite(scale)) {
+        return nullptr;
+    }
+    // we don't support scale in this range
+    if (scale > SK_Scalar1 || scale <= 0) {
+        return nullptr;
+    }
+    return sk_sp<SkImageFilter>(new SkDownSampleImageFilter(scale, std::move(input)));
+}
+
 sk_sp<SkSpecialImage> SkDownSampleImageFilter::onFilterImage(SkSpecialImage* source,
                                                              const Context& ctx,
                                                              SkIPoint* offset) const {
     if (fScale > SK_Scalar1 || fScale <= 0) {
         return nullptr;
     }
 
     int dstW = SkScalarRoundToInt(source->width() * fScale);
     int dstH = SkScalarRoundToInt(source->height() * fScale);
     if (dstW < 1) {
@@ skipping 62 matching lines @@
     this->INHERITED::flatten(buffer);
     buffer.writeScalar(fScale);
 }
 
 #ifndef SK_IGNORE_TO_STRING
 void SkDownSampleImageFilter::toString(SkString* str) const {
     str->appendf("SkDownSampleImageFilter: (");
     str->append(")");
 }
 #endif