Add SkEncodedInfo to report properties of encoded image data

src/codec/SkCodec.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 "SkBmpCodec.h"
 #include "SkCodec.h"
 #include "SkCodecPriv.h"
@@ skipping 96 matching lines @@
     return nullptr;
 }
 
 SkCodec* SkCodec::NewFromData(SkData* data, SkPngChunkReader* reader) {
     if (!data) {
         return nullptr;
     }
     return NewFromStream(new SkMemoryStream(data), reader);
 }
 
-SkCodec::SkCodec(const SkImageInfo& info, SkStream* stream, sk_sp<SkColorSpace> colorSpace,
+SkCodec::SkCodec(const SkEncodedInfo& info, SkStream* stream, sk_sp<SkColorSpace> colorSpace,
         Origin origin)
-    : fSrcInfo(info)
+    : fEncodedInfo(info)
+    , fSrcInfo(info.makeImageInfo())

[scroggo, 2016/03/23 14:48:50]

Alternatively, we could lazily create this when asked for. We would need to
change getInfo() to stop returning a reference, and how SkCodecImageGenerater
deals with it, so it would be a bigger change. If we do go that route, it should
be its own change, I think.

[msarett, 2016/03/24 16:20:44]

SGTM.

The reason that I did it this way is that, when I'm the client, I call getInfo()
over and over again (expecting it to be free).  I didn't want to force us to
create a new SkImageInfo on each call.

Another option would be to create an SkImageInfo on the first call and reuse it
on subsequent calls, but that may be unnecessarily complex.

     , fStream(stream)
     , fNeedsRewind(false)
     , fColorSpace(colorSpace)
     , fOrigin(origin)
     , fDstInfo()
     , fOptions()
     , fCurrScanline(-1)
 {}
 
 SkCodec::~SkCodec() {}
@@ skipping 251 matching lines @@
             SkASSERT(1 == linesRequested || this->getInfo().height() == linesRequested);
             const SkImageInfo fillInfo = info.makeWH(fillWidth, 1);
             for (int srcY = linesDecoded; srcY < linesRequested; srcY++) {
                 fillDst = SkTAddOffset<void>(dst, this->outputScanline(srcY) * rowBytes);
                 fill_proc(fillInfo, fillDst, rowBytes, fillValue, zeroInit, sampler);
             }
             break;
         }
     }
 }