Fix BitmapCopy_Texture test on iOS

tests/BitmapCopyTest.cpp

 /*
  * Copyright 2011 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 "SkRect.h"
 #include "SkTemplates.h"
@@ skipping 651 matching lines @@
             desc.fFlags = rt ? kRenderTarget_GrSurfaceFlag : kNone_GrSurfaceFlags;
             desc.fWidth = 2;
             desc.fHeight = 2;
             desc.fOrigin = kTopLeft_GrSurfaceOrigin;
 
             const void* srcData = (kSkia8888_GrPixelConfig == desc.fConfig) ? kData : swizData;
 
             SkAutoTUnref<GrTexture> texture(
                 ctx->textureProvider()->createTexture(desc, false, srcData, 0));
 
+            if (!texture) {
+                continue;
+            }
+
             SkBitmap srcBmp;
             GrWrapTextureInBitmap(texture, 2, 2, false, &srcBmp);
             if (srcBmp.isNull()) {
                 ERRORF(reporter, "Could not wrap texture in bitmap.");
                 continue;
             }
             static const SkColorType kDstCTs[] = { kRGBA_8888_SkColorType, kBGRA_8888_SkColorType };
             for (size_t dCT = 0; dCT < SK_ARRAY_COUNT(kDstCTs); ++dCT) {
                 SkBitmap dstBmp;
                 if (!srcBmp.copyTo(&dstBmp, kDstCTs[dCT])) {
@@ skipping 23 matching lines @@
                         }
                     }
                     dstBmpPixels += dstBmp.rowBytes();
                 }
             }
         }
     }
 }
 
 #endif