Add reallyHasAlpha() to SkAndroidCodec

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)
+    : INHERITED(codec)
 {}
 
 SkISize SkWebpAdapterCodec::onGetSampledDimensions(int sampleSize) const {
     float scale = get_scale_from_sample_size(sampleSize);
-    return fCodec->getScaledDimensions(scale);
+    return this->codec()->getScaledDimensions(scale);
 }
 
 bool SkWebpAdapterCodec::onGetSupportedSubset(SkIRect* desiredSubset) const {
-    return fCodec->getValidSubset(desiredSubset);
+    return this->codec()->getValidSubset(desiredSubset);
 }
 
 SkCodec::Result SkWebpAdapterCodec::onGetAndroidPixels(const SkImageInfo& info, void* pixels,
         size_t rowBytes, const 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,
+    return this->codec()->getPixels(info, pixels, rowBytes, &codecOptions, options.fColorPtr,
             options.fColorCount);
 }