telemetry: Fix key_silk_cases page whose content was offscreen

tools/perf/page_sets/data/key_silk_cases.json

 {
     "description": "Describes the Web Page Replay archives for a page set. Don't edit by hand! Use record_wpr for updating.", 
     "archives": {
         "key_silk_cases_009.wpr": [
             "http://jsfiddle.net/TLXLu/2/embedded/result/"
         ], 
+        "key_silk_cases_006.wpr": [
+            "http://jsfiddle.net/rF9Gh/3/embedded/result/"
+        ], 
         "key_silk_cases_000.wpr": [
             "http://staff.tumblr.com/", 
             "http://jsfiddle.net/mdxJ7/3/show", 
             "http://jsfiddle.net/3yDKh/1/show", 
             "http://jsfiddle.net/3yDKh/3/show"
         ], 
         "key_silk_cases_002.wpr": [
             "http://forecast.io?scroll", 
             "http://www.google.com/#q=google", 
             "http://forecast.io?swipe", 
             "http://pr.gg/scroll6.html", 
             "http://plus.google.com/app/basic/stream", 
             "http://forecast.io?tap", 
             "http://jsbin.com/UVIgUTa/6/quiet", 
             "http://mobile-news.sandbox.google.com/news/pt1", 
             "http://mobile-news.sandbox.google.com/news/pt0?scroll", 
             "http://mobile-news.sandbox.google.com/news/pt0?swipe", 
             "http://s.codepen.io/befamous/fullpage/pFsqb?scroll", 
             "http://s.codepen.io/befamous/fullpage/pFsqb?flip", 
             "http://s.codepen.io/befamous/fullpage/kbxnH?scroll", 
             "http://s.codepen.io/befamous/fullpage/kbxnH?select", 
             "http://famo.us?scroll", 
             "http://famo.us?tap"
         ], 
         "key_silk_cases_004.wpr": [
             "http://jankfree.org/silk/text-mask.html", 
             "http://jankfree.org/silk/rectangle_transition.html"
         ], 
-        "key_silk_cases_006.wpr": [
-            "http://jsfiddle.net/rF9Gh/3/embedded/result/"
+        "key_silk_cases_015.wpr": [
+            "http://jsfiddle.net/bNp2h/3/show/"
         ], 
         "key_silk_cases_008.wpr": [
             "http://jsfiddle.net/jx5De/13/embedded/result"
         ], 
         "key_silk_cases_011.wpr": [
             "http://jsfiddle.net/vBQHH/10/embedded/result/"
         ], 
         "key_silk_cases_001.wpr": [
             "http://groupcloned.com/test/plain/list-recycle-transform.html", 
             "http://groupcloned.com/test/plain/list-animation-simple.html", 
@@ skipping 41 matching lines @@
             "http://jsfiddle.net/ugkd4/10/show/", 
             "http://jsfiddle.net/xLuvC/1/show/", 
             "http://jsfiddle.net/bNp2h/2/show/", 
             "http://jsbin.com/UVIgUTa/38/quiet"
         ], 
         "key_silk_cases_013.wpr": [
             "http://jsfiddle.net/bNp2h/1/embedded/result/"
         ]
     }
 }