[System Health] Make pinterest/tumblr stories scroll to elements off screen.

tools/perf/page_sets/data/system_health_desktop.json

 {
     "archives": {
         "system_health_desktop_000.wpr": [
             "load:search:amazon",
             "load:search:flipkart",
             "load:search:ebay",
             "load:search:yandex",
             "load:search:taobao",
             "load:search:yahoo",
             "load:search:baidu"
@@ skipping 89 matching lines @@
             "long_running:tools:gmail-foreground",
             "long_running:tools:gmail-background"
         ],
         "system_health_desktop_030.wpr": [
             "play:media:soundcloud",
             "play:media:google_play_music"
         ],
         "system_health_desktop_032.wpr": [
             "play:media:pandora"
         ],
-        "system_health_desktop_033.wpr": [
+        "system_health_desktop_034.wpr": [
             "browse:media:pinterest",

[nednguyen, 2016/10/17 19:30:44]

IIRC, the record_wpr should erase these two entries & replace the
system_health_desktop.json with new mapping between wpr & page. If not, maybe
this is a bug

             "browse:media:tumblr"
+        ],
+        "system_health_desktop_035.wpr": [

[nednguyen, 2016/10/17 19:24:50]

Hmhh, this seems odd. Which wpr recording is "browse:media:pinterest" page
using? _034 or _035 wpr?

+            "browse:media:pinterest"
+        ],
+        "system_health_desktop_036.wpr": [
+            "browse:media:tumblr"
         ]
     },
     "description": "Describes the Web Page Replay archives for a story set. Don't edit by hand! Use record_wpr for updating."
-}
+}