Remove (almost) unused read/writeFunctionPtr API.

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 "SkBitmap.h"
 #include "SkBlurImageFilter.h"
 #include "SkCanvas.h"
@@ skipping 47 matching lines @@
 
 protected:
     sk_sp<SkSpecialImage> onFilterImage(SkSpecialImage* source, const Context& ctx,
                                         SkIPoint* offset) const override {
         REPORTER_ASSERT(fReporter, ctx.ctm() == fExpectedMatrix);
         offset->fX = offset->fY = 0;
         return sk_ref_sp<SkSpecialImage>(source);
     }
 
     void flatten(SkWriteBuffer& buffer) const override {
-        this->INHERITED::flatten(buffer);
-        buffer.writeFunctionPtr(fReporter);
-        buffer.writeMatrix(fExpectedMatrix);
+        SkDEBUGFAIL("Should never get here");
     }
 
 private:
     MatrixTestImageFilter(skiatest::Reporter* reporter, const SkMatrix& expectedMatrix)
         : INHERITED(nullptr, 0, nullptr)
         , fReporter(reporter)
         , fExpectedMatrix(expectedMatrix) {
     }
 
     skiatest::Reporter* fReporter;
@@ skipping 201 matching lines @@
     void addFilter(const char* name, sk_sp<SkImageFilter> filter) {
         fFilters.push_back(Filter(name, std::move(filter)));
     }
 
     SkTArray<Filter> fFilters;
 };
 
 }
 
 sk_sp<SkFlattenable> MatrixTestImageFilter::CreateProc(SkReadBuffer& buffer) {
-    SK_IMAGEFILTER_UNFLATTEN_COMMON(common, 1);
-    skiatest::Reporter* reporter = (skiatest::Reporter*)buffer.readFunctionPtr();
-    SkMatrix matrix;
-    buffer.readMatrix(&matrix);
-    return MatrixTestImageFilter::Make(reporter, matrix);
+    SkDEBUGFAIL("Should never get here");
+    return nullptr;
 }
 
 #ifndef SK_IGNORE_TO_STRING
 void MatrixTestImageFilter::toString(SkString* str) const {
     str->appendf("MatrixTestImageFilter: (");
     str->append(")");
 }
 #endif
 
 static sk_sp<SkImage> make_small_image() {
@@ skipping 1424 matching lines @@
         { SkColorFilterImageFilter::Make(cf, blif), false },
         { SkMergeImageFilter::Make(cfif, blif),     false },
         { SkComposeImageFilter::Make(blif, cfif),   false },
     };
     
     for (const auto& rec : recs) {
         const bool canHandle = rec.fFilter->canHandleComplexCTM();
         REPORTER_ASSERT(reporter, canHandle == rec.fExpectCanHandle);
     }
 }