rebaseline_server: use just skpdiff, not Python Image Library

tools/skpdiff/SkDifferentPixelsMetric_opencl.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 "SkDifferentPixelsMetric.h"
@@ skipping 18 matching lines @@
     "                                                                           \n"
     "        atomic_inc(result);                                                \n"
     "        // TODO: generate alpha mask                                       \n"
     "    }                                                                      \n"
     "}                                                                          \n";
 
 const char* SkDifferentPixelsMetric::getName() const {
     return "different_pixels";
 }
 
-bool SkDifferentPixelsMetric::diff(SkBitmap* baseline, SkBitmap* test, bool computeMask,
+bool SkDifferentPixelsMetric::diff(SkBitmap* baseline, SkBitmap* test, bool computeAlphaMask,
+                                   bool computeRgbDiff, bool computeWhiteDiff,
                                    Result* result) const {
     double startTime = get_seconds();
 
     if (!fIsGood) {
         return false;
     }
 
     // If we never end up running the kernel, include some safe defaults in the result.
     result->poiCount = 0;
 
@@ skipping 61 matching lines @@
     return true;
 }
 
 bool SkDifferentPixelsMetric::onInit() {
     if (!this->loadKernelSource(kDifferentPixelsKernelSource, "diff", &fKernel)) {
         return false;
     }
 
     return true;
 }