add runtime option to provide data->imagegenerator factory

gm/factory.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "gm.h"
 
 #include "Resources.h"
@@ skipping 18 matching lines @@
 protected:
     void onOnceBeforeDraw() override {
         // Copyright-free file from http://openclipart.org/detail/29213/paper-plane-by-ddoo
         SkString pngFilename = GetResourcePath("plane.png");
         SkAutoDataUnref data(SkData::NewFromFileName(pngFilename.c_str()));
         if (data.get()) {
             // Create a cache which will boot the pixels out anytime the
             // bitmap is unlocked.
             SkAutoTUnref<SkDiscardableMemoryPool> pool(
                 SkDiscardableMemoryPool::Create(1));
-            SkAssertResult(SkInstallDiscardablePixelRef(SkImageGenerator::NewFromData(data),
+            SkAssertResult(SkInstallDiscardablePixelRef(SkImageGenerator::NewFromEncoded(data),
                                                         NULL, &fBitmap, pool));
         }
     }
 
     SkString onShortName() override {
         return SkString("factory");
     }
 
     SkISize onISize() override {
         return SkISize::Make(640, 480);
     }
 
     void onDraw(SkCanvas* canvas) override {
         canvas->drawBitmap(fBitmap, 0, 0);
     }
 
 private:
     SkBitmap fBitmap;
 
     typedef GM INHERITED;
 };
 
 //////////////////////////////////////////////////////////////////////////////
 
 static GM* MyFactory(void*) { return new FactoryGM; }
 static GMRegistry reg(MyFactory);
 
 }  // namespace skiagm