Add swipe_to_dismiss to Silk benchmark

tools/perf/page_sets/key_silk_cases.json

 {
   "description": "Pages hand-picked for project Silk.",
   "archive_data_file": "data/key_silk_cases.json",
   "credentials_path": "data/credentials.json",
   "user_agent_type": "mobile",
   "smoothness": { "action": "scroll" },
   "navigate_steps" : [
     { "action": "navigate" },
     { "action": "wait", "seconds": 2 }
   ],
@@ skipping 118 matching lines @@
     },
     {
       "url": "file://key_silk_cases/rectangle_transition.html",
       "smoothness": { "action": "wait", "seconds": 5 }
     },
     {
       "url": "file://key_silk_cases/font_wipe.html",
       "smoothness": { "action": "wait", "seconds": 5 }
     },
     {
+      "url": "file://key_silk_cases/inbox_app.html?swipe_to_dismiss",
+      "navigate_steps" : [
+        { "action": "navigate" },
+        { "action": "wait", "seconds": 2 }
+      ],
+      "smoothness": {
+        "action": "swipe_to_dismiss"
+      },
+      "swipe_to_dismiss": [
+        {
+          "action": "swipe",
+          "element_function": "function(callback) { callback(document.getElementsByClassName('message')[2]); }",
+          "distance": 200,
+          "direction": "left",
+          "left_start_percentage": 0.8,
+          "top_start_percentage": 0.2,
+          "wait_after": {
+            "javascript": "document.getElementsByClassName('message').length < 18"
+          }
+        }
+      ]
+    },
+    {
+      "url": "file://key_silk_cases/inbox_app.html?stress_hidey_bars",
+      "navigate_steps" : [
+        { "action": "navigate" },
+        { "action": "wait", "seconds": 2 }
+      ],
+      "smoothness": {
+        "action": "stress_hidey_bars"
+      },
+      "stress_hidey_bars": [
+        {
+          "action": "scroll",
+          "scrollable_element_function": "function(callback) { callback(document.getElementById('messages')); }",
+          "direction": "down",
+          "speed": 200
+        },
+        {
+          "action": "scroll",
+          "scrollable_element_function": "function(callback) { callback(document.getElementById('messages')); }",
+          "direction": "up",
+          "speed": 200
+        },
+        {
+          "action": "scroll",
+          "scrollable_element_function": "function(callback) { callback(document.getElementById('messages')); }",
+          "direction": "down",
+          "speed": 200
+        }
+      ]
+    },
+    {
       "url": "file://key_silk_cases/inbox_app.html?toggle_drawer",
       "navigate_steps" : [
         { "action": "navigate" },
         { "action": "wait", "seconds": 2 }
       ],
       "smoothness": {
         "action": "toggle_drawer",
         "repeat": 6
       },
       "toggle_drawer": [
         {
           "action": "click_element",
           "selector": "#menu-button"
         },
         { "action": "wait", "seconds": 1 }
       ]
     },
     {
-      "url": "file://key_silk_cases/inbox_app.html?slide_drawer",
+      "url": "file://key_silk_cases/old_inbox_app.html?slide_drawer",
       "navigate_steps" : [
         { "action": "navigate" },
         { "action": "wait", "seconds": 2 }
       ],
       "smoothness": {
         "action": "slide_drawer"
       },
       "slide_drawer": [
         {
           "action": "swipe",
           "element_function": "function(callback) { callback(document.getElementById('nav-drawer')); }",
           "distance": 200,
           "direction": "left",
           "left_start_percentage": 0.8,
           "top_start_percentage": 0.2,
           "wait_after": {
             "javascript": "!document.getElementById('nav-drawer').active"
           }
         }
       ]
     }
   ]
 }