guarded change to SkImageGenerator to make getInfo() const

tests/ImageGeneratorTest.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"
 #include "Test.h"
 
+class MyImageGenerator : public SkImageGenerator {
+public:
+    MyImageGenerator() : SkImageGenerator(SkImageInfo::MakeN32Premul(0, 0)) {}
+};
+
 DEF_TEST(ImageGenerator, reporter) {
-    SkImageGenerator ig;
+    MyImageGenerator ig;
     SkISize sizes[3];
     sizes[0] = SkISize::Make(200, 200);
     sizes[1] = SkISize::Make(100, 100);
     sizes[2] = SkISize::Make( 50,  50);
     void*   planes[3] = { NULL };
     size_t  rowBytes[3] = { 0 };
     SkYUVColorSpace colorSpace;
 
     // Check that the YUV decoding API does not cause any crashes
     ig.getYUV8Planes(sizes, NULL, NULL, &colorSpace);
     ig.getYUV8Planes(sizes, NULL, NULL, NULL);
     ig.getYUV8Planes(sizes, planes, NULL, NULL);
     ig.getYUV8Planes(sizes, NULL, rowBytes, NULL);
     ig.getYUV8Planes(sizes, planes, rowBytes, NULL);
     ig.getYUV8Planes(sizes, planes, rowBytes, &colorSpace);
 
     int dummy;
     planes[0] = planes[1] = planes[2] = &dummy;
     rowBytes[0] = rowBytes[1] = rowBytes[2] = 250;
 
     ig.getYUV8Planes(sizes, planes, rowBytes, &colorSpace);
 }