remove getter for imagegenerator factory, update test

src/core/SkImageGenerator.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 "SkImageGenerator.h"
 
 bool SkImageGenerator::getPixels(const SkImageInfo& info, void* pixels, size_t rowBytes,
@@ skipping 117 matching lines @@
 bool SkImageGenerator::onGetPixels(const SkImageInfo& info, void* dst, size_t rb,
                                    SkPMColor* colors, int* colorCount) {
     return false;
 }
 #endif
 
 ///////////////////////////////////////////////////////////////////////////////////////////////////
 
 #include "SkGraphics.h"
 
-static SkGraphics::ImageGeneratorFromEncodedFactory gImageGeneratorFromEncodedFactory;
+static SkGraphics::ImageGeneratorFromEncodedFactory gFactory;
 
-SkGraphics::ImageGeneratorFromEncodedFactory SkGraphics::GetImageGeneratorFromEncodedFactory() {
-    return gImageGeneratorFromEncodedFactory;
-}
-
-void SkGraphics::SetImageGeneratorFromEncodedFactory(ImageGeneratorFromEncodedFactory factory) {
-    gImageGeneratorFromEncodedFactory = factory;
+SkGraphics::ImageGeneratorFromEncodedFactory
+SkGraphics::SetImageGeneratorFromEncodedFactory(ImageGeneratorFromEncodedFactory factory)
+{
+    ImageGeneratorFromEncodedFactory prev = gFactory;
+    gFactory = factory;
+    return prev;
 }
 
 SkImageGenerator* SkImageGenerator::NewFromEncoded(SkData* data) {
     if (NULL == data) {
         return NULL;
     }
-    if (gImageGeneratorFromEncodedFactory) {
-        if (SkImageGenerator* generator = gImageGeneratorFromEncodedFactory(data)) {
+    if (gFactory) {
+        if (SkImageGenerator* generator = gFactory(data)) {
             return generator;
         }
     }
     return SkImageGenerator::NewFromEncodedImpl(data);
 }