Add scaled subset API to SkCodec

tests/CodexTest.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "Resources.h"
 #include "SkBitmap.h"
 #include "SkCodec.h"
@@ skipping 221 matching lines @@
         return;
     }
 
     SkRandom rand;
     SkIRect subset;
     SkCodec::Options opts;
     opts.fSubset = ⊂
     for (int i = 0; i < 5; i++) {
         subset = generate_random_subset(&rand, size.width(), size.height());
         SkASSERT(!subset.isEmpty());
-        const bool supported = codec->getValidSubset(&subset);
+        const bool supported = codec->getScaledSubsetDimensions(1.0f, opts);
         REPORTER_ASSERT(r, supported == supportsSubsetDecoding);
 
         SkImageInfo subsetInfo = info.makeWH(subset.width(), subset.height());
         SkBitmap bm;
         bm.allocPixels(subsetInfo);
         const SkCodec::Result result = codec->getPixels(bm.info(), bm.getPixels(), bm.rowBytes(),
                                                         &opts, nullptr, nullptr);
 
         if (supportsSubsetDecoding) {
             REPORTER_ASSERT(r, result == expectedResult);
@@ skipping 336 matching lines @@
     REPORTER_ASSERT(r, SkCodec::kInvalidParameters == result);
     result = decoder->startScanlineDecode(
         decoder->getInfo().makeColorType(kIndex_8_SkColorType));
     REPORTER_ASSERT(r, SkCodec::kInvalidParameters == result);
 }
 
 DEF_TEST(Codec_Params, r) {
     test_invalid_parameters(r, "index8.png");
     test_invalid_parameters(r, "mandrill.wbmp");
 }