add helpers for using SkData with picture serialization

samplecode/GMSampleView.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 "GMSampleView.h"
 
 GMSampleView::GMSampleView(GM* gm) : fShowSize(false), fGM(gm) {}
@@ skipping 29 matching lines @@
 
 bool GMSampleView::onEvent(const SkEvent& evt) {
     if (evt.isType("GMSampleView::showSize")) {
         fShowSize = SkToBool(evt.getFast32());
         return true;
     }
     return this->INHERITED::onEvent(evt);
 }
 
 #include "SkPicture.h"
-#include "SkStream.h"
 static sk_sp<SkPicture> round_trip_serialize(SkPicture* src) {
-    SkDynamicMemoryWStream stream;
-    src->serialize(&stream);
-    SkAutoTDelete<SkStream> reader(stream.detachAsStream());
-    return SkPicture::MakeFromStream(reader);
+    return SkPicture::MakeFromData(src->serialize().get());
 }
 
 #include "SkPictureRecorder.h"
 void GMSampleView::onDrawContent(SkCanvas* canvas) {
     SkPictureRecorder recorder;
     SkCanvas* origCanvas = canvas;
 
     if (false) {
         SkISize size = fGM->getISize();
         canvas = recorder.beginRecording(SkRect::MakeIWH(size.width(), size.height()));
@@ skipping 23 matching lines @@
     }
 }
 
 void GMSampleView::onDrawBackground(SkCanvas* canvas) {
     fGM->drawBackground(canvas);
 }
 
 bool GMSampleView::onAnimate(const SkAnimTimer& timer) {
     return fGM->animate(timer);
 }