add ImageGenerator::NewFromData to porting layer

gm/colorwheel.cpp

 /*
  * Copyright 2014 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 "SkData.h"
-#include "SkDecodingImageGenerator.h"
 #include "gm.h"
 #include "sk_tool_utils.h"
 
 static void checkerboard(
         SkCanvas* canvas, int w, int h, int size, SkColor c1, SkColor c2) {
     SkAutoCanvasRestore autoCanvasRestore(canvas, true);
     canvas->clipRect(SkRect::MakeWH(SkIntToScalar(w), SkIntToScalar(h)));
     canvas->drawColor(c1);
     SkPaint paint;
     paint.setColor(c2);
@@ skipping 50 matching lines @@
     canvas->drawText("B", 1, 40.0f, 20.0f, paint);
     paint.setColor(SK_ColorCYAN);
     canvas->drawText("C", 1, 56.0f, 20.0f, paint);
     paint.setColor(SK_ColorMAGENTA);
     canvas->drawText("M", 1, 72.0f, 20.0f, paint);
     paint.setColor(SK_ColorYELLOW);
     canvas->drawText("Y", 1, 88.0f, 20.0f, paint);
     paint.setColor(SK_ColorBLACK);
     canvas->drawText("K", 1, 104.0f, 20.0f, paint);
 }