Extend the BigJs benchmark: add a YouTube page.

The page uses a big parsing blocking script and is thus interesting for the
BigJs benchmark.

R=skyostil@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1060563005

Cr-Commit-Position: refs/heads/master@{#324038}

tools/perf/page_sets/big_js.py

@@ -14,11 +14,14 @@ class BigJsPageSet(page_set_module.PageSet):
       bucket=page_set_module.PARTNER_BUCKET,
       user_agent_type='desktop')
 
-    # Page sets with only one page don't work well, since we end up reusing a
+    # www.foo.com is a dummy page to make it easier to run only one interesting
+    # page at a time. You can't just run the interesting page on its own: Page
+    # sets with only one page don't work well, since we end up reusing a
     # renderer all the time and it keeps its memory caches alive (see
-    # crbug.com/403735). Add a dummy second page here.
+    # crbug.com/403735).
     urls_list = [
        'http://beta.unity3d.com/jonas/DT2/',
+       'https://www.youtube.com/watch?v=IJNR2EpS0jw',
        'http://www.foo.com',
     ]
     for url in urls_list:

tools/perf/page_sets/data/big_js.json

 {
-    "description": "Describes the Web Page Replay archives for a page set. Don't edit by hand! Use record_wpr for updating.", 
+    "description": "Describes the Web Page Replay archives for a user story set. Don't edit by hand! Use record_wpr for updating.", 
     "archives": {
         "big_js_000.wpr": [
             "http://beta.unity3d.com/jonas/DT2/", 
             "http://www.foo.com"
+        ], 
+        "big_js_001.wpr": [
+            "https://www.youtube.com/watch?v=IJNR2EpS0jw"
         ]
     }
 }
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tools/perf/page_sets/data/big_js_001.wpr.sha1

+5fa638992033ae0234148c6060af998ec23462f9
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