Bugfix that cause skpdiff to segfault.

gm/rebaseline_server/testdata/outputs/expected/compare_rendered_pictures_test.CompareRenderedPicturesTest.test_endToEnd_withImageBaseGSUrl/compare_rendered_pictures.json

Index: gm/rebaseline_server/testdata/outputs/expected/compare_rendered_pictures_test.CompareRenderedPicturesTest.test_endToEnd_withImageBaseGSUrl/compare_rendered_pictures.json
diff --git a/gm/rebaseline_server/testdata/outputs/expected/compare_rendered_pictures_test.CompareRenderedPicturesTest.test_endToEnd_withImageBaseGSUrl/compare_rendered_pictures.json b/gm/rebaseline_server/testdata/outputs/expected/compare_rendered_pictures_test.CompareRenderedPicturesTest.test_endToEnd_withImageBaseGSUrl/compare_rendered_pictures.json
index e62b5cbc634c74e10058be2274f3fcf521809538..1026014da54e5417fcb04ea3573c94fabf9c1022 100644
--- a/gm/rebaseline_server/testdata/outputs/expected/compare_rendered_pictures_test.CompareRenderedPicturesTest.test_endToEnd_withImageBaseGSUrl/compare_rendered_pictures.json
+++ b/gm/rebaseline_server/testdata/outputs/expected/compare_rendered_pictures_test.CompareRenderedPicturesTest.test_endToEnd_withImageBaseGSUrl/compare_rendered_pictures.json
@@ -128,7 +128,7 @@
     "renderModeB"
   ], 
   "header": {
-    "dataHash": "-5707186260478709107", 
+    "dataHash": "-9145196899696949575", 
     "isEditable": false, 
     "isExported": true, 
     "schemaVersion": 5, 
@@ -162,8 +162,8 @@
         "tiledOrWhole": "whole", 
         "tilenum": "N/A"
       }, 
-      "imageAUrl": "changed_skp/bitmap-64bitMD5_3101044995537104462.png", 
-      "imageBUrl": "changed_skp/bitmap-64bitMD5_13623922271964399662.png", 
+      "imageAUrl": "changed_skp/bitmap-64bitMD5_17527938180154630042.png", 
+      "imageBUrl": "changed_skp/bitmap-64bitMD5_2314401992566164894.png", 
       "isDifferent": true, 
       "sourceJsonFile": "./summary.json"
     }, 
@@ -179,7 +179,7 @@
         "tilenum": "N/A"
       }, 
       "imageAUrl": null, 
-      "imageBUrl": "only-in-after_skp/bitmap-64bitMD5_2320185040577047131.png", 
+      "imageBUrl": "only-in-after_skp/bitmap-64bitMD5_6558642089737589931.png", 
       "isDifferent": true, 
       "sourceJsonFile": "./summary.json"
     }, 
@@ -194,7 +194,7 @@
         "tiledOrWhole": "whole", 
         "tilenum": "N/A"
       }, 
-      "imageAUrl": "only-in-before_skp/bitmap-64bitMD5_2320185040577047131.png", 
+      "imageAUrl": "only-in-before_skp/bitmap-64bitMD5_6558642089737589931.png", 
       "imageBUrl": null, 
       "isDifferent": true, 
       "sourceJsonFile": "./summary.json"
@@ -210,8 +210,8 @@
         "tiledOrWhole": "whole", 
         "tilenum": "N/A"
       }, 
-      "imageAUrl": "unchanged_skp/bitmap-64bitMD5_3322248763049618493.png", 
-      "imageBUrl": "unchanged_skp/bitmap-64bitMD5_3322248763049618493.png", 
+      "imageAUrl": "unchanged_skp/bitmap-64bitMD5_1094324242976325446.png", 
+      "imageBUrl": "unchanged_skp/bitmap-64bitMD5_1094324242976325446.png", 
       "isDifferent": false, 
       "sourceJsonFile": "./summary.json"
     }