Implement support for expanding crop rects in image filters

tests/ImageFilterTest.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 "SkBicubicImageFilter.h"
 #include "SkBitmap.h"
 #include "SkBitmapDevice.h"
@@ skipping 228 matching lines @@
         SkTileImageFilter::Create(inputCropRect.rect(), cropRect.rect(), input.get()),
         SkXfermodeImageFilter::Create(SkXfermode::Create(SkXfermode::kSrcOver_Mode), input.get(), input.get(), &cropRect),
     };
 
     for (size_t i = 0; i < SK_ARRAY_COUNT(filters); ++i) {
         SkImageFilter* filter = filters[i];
         SkBitmap result;
         SkIPoint offset;
         SkString str;
         str.printf("filter %d", static_cast<int>(i));
-        SkImageFilter::Context ctx(SkMatrix::I(), SkIRect::MakeEmpty());
+        SkImageFilter::Context ctx(SkMatrix::I(), SkIRect::MakeLargest());
         REPORTER_ASSERT_MESSAGE(reporter, filter->filterImage(&proxy, bitmap, ctx, &result, &offset), str.c_str());
         REPORTER_ASSERT_MESSAGE(reporter, offset.fX == 20 && offset.fY == 30, str.c_str());
     }
 
     for (size_t i = 0; i < SK_ARRAY_COUNT(filters); ++i) {
         SkSafeUnref(filters[i]);
     }
 }
 
 DEF_TEST(ImageFilterCropRect, reporter) {
@@ skipping 37 matching lines @@
 
 #if SK_SUPPORT_GPU
 DEF_GPUTEST(ImageFilterCropRectGPU, reporter, factory) {
     GrContext* context = factory->get(static_cast<GrContextFactory::GLContextType>(0));
     SkAutoTUnref<SkGpuDevice> device(SkGpuDevice::Create(context,
                                                          SkImageInfo::MakeN32Premul(100, 100),
                                                          0));
     test_crop_rects(device, reporter);
 }
 #endif