Include screenshots in css test html log

python/requirements.txt

@@ -2,7 +2,7 @@ blessings == 1.6
 mach == 0.6.0
 mozdebug == 0.1
 mozinfo == 0.8
-mozlog == 3.0
+mozlog == 3.2
 toml == 0.9.1
 
 # For Python linting

tests/wpt/harness/requirements.txt

@@ -1,4 +1,4 @@
 html5lib >= 0.99
 mozinfo >= 0.7
-mozlog >= 3.0
+mozlog >= 3.2
 mozdebug >= 0.1

tests/wpt/harness/wptrunner/executors/base.py

@@ -291,9 +291,17 @@ def run_test(self, test):
         log_data = [{"url": nodes[0].url, "screenshot": screenshots[0]}, relation,
                     {"url": nodes[1].url, "screenshot": screenshots[1]}]
 
+        # image1/2 and differences are for mozlog 3.2 html logs
+        extra = {
+            'image1':'data:image/png;base64,' + screenshots[0],
+            'image2':'data:image/png;base64,' + screenshots[1],
+            'differences': "Not Implemented",
+            'reftest_screenshots':log_data
+        }
+
         return {"status": "FAIL",
                 "message": "\n".join(self.message),
-                "extra": {"reftest_screenshots": log_data}}
+                "extra": extra}
 
     def retake_screenshot(self, node, viewport_size, dpi):
         success, data = self.executor.screenshot(node, viewport_size, dpi)