add runtime option to provide data->imagegenerator factory

tests/CachedDecodingPixelRefTest.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBitmap.h"
 #include "SkCachingPixelRef.h"
 #include "SkCanvas.h"
@@ skipping 124 matching lines @@
                 continue;
             }
         }
         bool comparePixels = (SkImageEncoder::kPNG_Type == type);
         compare_bitmaps(reporter, original, lazy, comparePixels);
     }
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 static bool install_skCachingPixelRef(SkData* encoded, SkBitmap* dst) {
-    return SkCachingPixelRef::Install(SkImageGenerator::NewFromData(encoded), dst);
+    return SkCachingPixelRef::Install(SkImageGenerator::NewFromEncoded(encoded), dst);
 }
 static bool install_skDiscardablePixelRef(SkData* encoded, SkBitmap* dst) {
     // Use system-default discardable memory.
     return SkInstallDiscardablePixelRef(encoded, dst);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 /**
  *  This checks to see that a SkCachingPixelRef and a
  *  SkDiscardablePixelRef works as advertised with a
@@ skipping 196 matching lines @@
         canvas.clear(kDefaultColor);
         canvas.drawImage(image, 0, 0, NULL);
         if (TestImageGenerator::kSucceedGetPixels_TestType == test) {
             REPORTER_ASSERT(
                     r, TestImageGenerator::Color() == *bitmap.getAddr32(0, 0));
         } else {
             REPORTER_ASSERT(r, kDefaultColor == bitmap.getColor(0,0));
         }
     }
 }