Create an SkAndroidCodec API separate from SkCodec

src/codec/SkWebpAdapterCodec.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 "SkCodec.h"
+#include "SkCodecPriv.h"
+#include "SkWebpAdapterCodec.h"
+
+SkWebpAdapterCodec::SkWebpAdapterCodec(SkWebpCodec* codec)
+    : INHERITED(codec->getInfo())
+    , fCodec(codec)
+{}
+
+SkISize SkWebpAdapterCodec::onGetSampledDimensions(int sampleSize) const {
+    float scale = get_scale_from_sample_size(sampleSize);
+    return fCodec->getScaledDimensions(scale);
+}
+
+bool SkWebpAdapterCodec::onGetSupportedSubset(SkIRect* desiredSubset) const {
+    return fCodec->getValidSubset(desiredSubset);
+}
+
+SkCodec::Result SkWebpAdapterCodec::onGetAndroidPixels(const SkImageInfo& info, void* pixels,
+        size_t rowBytes, AndroidOptions& options) {
+    // SkWebpCodec will support pretty much any dimensions that we provide, but we want
+    // to be stricter about the type of scaling that we allow, so we will add an extra
+    // check here.
+    SkISize supportedSize;
+    if (!options.fSubset) {
+        supportedSize = this->onGetSampledDimensions(options.fSampleSize);
+    } else {
+        supportedSize = this->getSampledSubsetDimensions(options.fSampleSize, *options.fSubset);
+    }
+    if (supportedSize != info.dimensions()) {
+        return SkCodec::kInvalidParameters;
+    }
+
+    SkCodec::Options codecOptions;
+    codecOptions.fZeroInitialized = options.fZeroInitialized;
+    codecOptions.fSubset = options.fSubset;
+    return fCodec->getPixels(info, pixels, rowBytes, &codecOptions, options.fColorPtr,
+            options.fColorCount);
+}