SkPixelSerializer: remove deprecated virtual

tests/ImageTest.cpp

 /*
  * Copyright 2015 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 "SkCanvas.h"
 #include "SkData.h"
@@ skipping 151 matching lines @@
 public:
     MockSerializer(SkData* (*func)()) : fFunc(func), fDidEncode(false) { }
 
     bool didEncode() const { return fDidEncode; }
 
 protected:
     bool onUseEncodedData(const void*, size_t) override {
         return false;
     }
 
-    SkData* onEncodePixels(const SkImageInfo&, const void*, size_t) override {
+    SkData* onEncode(const SkPixmap&) override {
         fDidEncode = true;
         return fFunc();
     }
 
 private:
     SkData* (*fFunc)();
     bool fDidEncode;
 
     typedef SkPixelSerializer INHERITED;
 };
@@ skipping 484 matching lines @@
     check_image_color(reporter, refImg, expected1);
 #endif
     check_image_color(reporter, cpyImg, expected0);
 
     // Now exercise the release proc
     REPORTER_ASSERT(reporter, 0 == releaseChecker.fReleaseCount);
     refImg.reset(nullptr); // force a release of the image
     REPORTER_ASSERT(reporter, 1 == releaseChecker.fReleaseCount);
 }
 #endif