Remove (almost) unused read/writeFunctionPtr API.

src/core/SkReadBuffer.cpp

 /*
  * Copyright 2012 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 "SkErrorInternals.h"
 #include "SkImage.h"
@@ skipping 374 matching lines @@
         if (sizeRecorded != sizeRead) {
             this->validate(false);
             return nullptr;
         }
     } else {
         // we must skip the remaining data
         fReader.skip(sizeRecorded);
     }
     return obj.release();
 }
-
-/**
- *  Needs to follow the same pattern as readFlattenable(), but explicitly skip whatever data
- *  has been written.
- */
-void SkReadBuffer::skipFlattenable() {
-    if (fFactoryCount > 0) {
-        if (0 == fReader.readU32()) {
-            return;
-        }
-    } else {
-        if (nullptr == this->readFunctionPtr()) {
-            return;
-        }
-    }
-    uint32_t sizeRecorded = fReader.readU32();
-    fReader.skip(sizeRecorded);
-}