Fix crash when ETC1 codec is not supported.

gm/etc1bitmap.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 "gm.h"
 
 #include "Resources.h"
@@ skipping 87 matching lines @@
         SkBitmap bm;
         SkString filename = GetResourcePath("mandrill_128.");
         filename.append(this->fileExtension());
         SkAutoTUnref<SkData> fileData(SkData::NewFromFileName(filename.c_str()));
         if (nullptr == fileData) {
             SkDebugf("Could not open the file. Did you forget to set the resourcePath?\n");
             return;
         }
 
         SkAutoTUnref<SkImage> image(SkImage::NewFromEncoded(fileData));
+        if (nullptr == image) {
+            SkDebugf("Could not decode the ETC file. ETC may not be included in this platform.\n");
+            return;
+        }
         canvas->drawImage(image, 0, 0);
     }
 
 private:
     typedef GM INHERITED;
 };
 
 // This class specializes ETC1BitmapGM to load the mandrill_128.pkm file.
 class ETC1Bitmap_PKM_GM : public ETC1BitmapGM {
 public:
@@ skipping 94 matching lines @@
 
 //////////////////////////////////////////////////////////////////////////////
 
 DEF_GM(return new skiagm::ETC1Bitmap_PKM_GM;)
 DEF_GM(return new skiagm::ETC1Bitmap_KTX_GM;)
 DEF_GM(return new skiagm::ETC1Bitmap_R11_KTX_GM;)
 
 #ifndef SK_IGNORE_ETC1_SUPPORT
 DEF_GM(return new skiagm::ETC1Bitmap_NPOT_GM;)
 #endif  // SK_IGNORE_ETC1_SUPPORT