GM: create GmResultDigest that encapsulates digest type ("bitmap-64bitMD5") and value (12345)

tools/skimage_main.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "gm_expectations.h"
 #include "SkBitmap.h"
 #include "SkBitmapHasher.h"
@@ skipping 201 matching lines @@
 
     skiagm::Expectations jsExpectation = gJsonExpectations->get(filename);
     if (jsExpectation.empty()) {
         if (failureArray != NULL) {
             failureArray->push_back().printf("decoded %s, but could not find expectation.",
                                              filename);
         }
         return false;
     }
 
-    SkHashDigest checksum;
+    uint64_t checksum;
     if (!SkBitmapHasher::ComputeDigest(bitmap, &checksum)) {
         if (failureArray != NULL) {
             failureArray->push_back().printf("decoded %s, but could not create a checksum.",
                                              filename);
         }
         return false;
     }
 
     if (jsExpectation.match(checksum)) {
         return true;
@@ skipping 332 matching lines @@
     }
 
     return failed ? -1 : 0;
 }
 
 #if !defined SK_BUILD_FOR_IOS
 int main(int argc, char * const argv[]) {
     return tool_main(argc, (char**) argv);
 }
 #endif