Revert of SkRTConf: reduce functionality to what we use, increase simplicity

src/images/SkPNGImageEncoder.cpp

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkImageEncoder.h"
 #include "SkColor.h"
 #include "SkColorPriv.h"
 #include "SkDither.h"
 #include "SkMath.h"
+#include "SkRTConf.h"
 #include "SkStream.h"
 #include "SkTemplates.h"
 #include "SkUtils.h"
 #include "transform_scanline.h"
 
 #include "png.h"
 
 /* These were dropped in libpng >= 1.4 */
 #ifndef png_infopp_NULL
 #define png_infopp_NULL nullptr
 #endif
 
 #ifndef png_bytepp_NULL
 #define png_bytepp_NULL nullptr
 #endif
 
 #ifndef int_p_NULL
 #define int_p_NULL nullptr
 #endif
 
 #ifndef png_flush_ptr_NULL
 #define png_flush_ptr_NULL nullptr
 #endif
 
 #define DEFAULT_FOR_SUPPRESS_PNG_IMAGE_DECODER_WARNINGS true
-// Suppress most PNG warnings when calling image decode functions.
-static const bool c_suppressPNGImageDecoderWarnings{
-    DEFAULT_FOR_SUPPRESS_PNG_IMAGE_DECODER_WARNINGS};
+SK_CONF_DECLARE(bool, c_suppressPNGImageDecoderWarnings,
+                "images.png.suppressDecoderWarnings",
+                DEFAULT_FOR_SUPPRESS_PNG_IMAGE_DECODER_WARNINGS,
+                "Suppress most PNG warnings when calling image decode "
+                "functions.");
 
 ///////////////////////////////////////////////////////////////////////////////
 
 #include "SkColorPriv.h"
 #include "SkUnPreMultiply.h"
 
 static void sk_error_fn(png_structp png_ptr, png_const_charp msg) {
     if (!c_suppressPNGImageDecoderWarnings) {
         SkDEBUGF(("------ png error %s\n", msg));
     }
@@ skipping 281 matching lines @@
 
 ///////////////////////////////////////////////////////////////////////////////
 DEFINE_ENCODER_CREATOR(PNGImageEncoder);
 ///////////////////////////////////////////////////////////////////////////////
 
 SkImageEncoder* sk_libpng_efactory(SkImageEncoder::Type t) {
     return (SkImageEncoder::kPNG_Type == t) ? new SkPNGImageEncoder : nullptr;
 }
 
 static SkImageEncoder_EncodeReg gEReg(sk_libpng_efactory);