hide discardable factory from public imagegenerator api

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 "SkCanvas.h"
 #include "SkData.h"
 #include "SkDecodingImageGenerator.h"
 #include "SkDiscardableMemoryPool.h"
 #include "SkDiscardablePixelRef.h"
 #include "SkImageDecoder.h"
-#include "SkImageGenerator.h"
+#include "SkImageGeneratorPriv.h"
 #include "SkOSFile.h"
 #include "SkStream.h"
 
 namespace skiagm {
 
 /**
  *  Draw a PNG created by SkBitmapFactory.
  */
 class FactoryGM : public GM {
 public:
@@ skipping 39 matching lines @@
 
     typedef GM INHERITED;
 };
 
 //////////////////////////////////////////////////////////////////////////////
 
 static GM* MyFactory(void*) { return new FactoryGM; }
 static GMRegistry reg(MyFactory);
 
 }  // namespace skiagm