[dashboard] Use "dialog-dismiss" and "dialog-confirm" w/ paper-dialogs

dashboard/dashboard/elements/trace-form.html

Index: dashboard/dashboard/elements/trace-form.html
diff --git a/dashboard/dashboard/elements/trace-form.html b/dashboard/dashboard/elements/trace-form.html
index 193d9b7ea417ef119570f4b3ea9d6a634f36b71d..9018cb1ad1e32e729e5ff01c6764b87685f05a57 100644
--- a/dashboard/dashboard/elements/trace-form.html
+++ b/dashboard/dashboard/elements/trace-form.html
@@ -46,7 +46,7 @@ the trace process after the user clicks on the trace button.
           padding: 1px 2px;
         }
 
-        paper-button[affirmative] {
+        paper-button[dialog-confirm] {
           background: #4285f4;
           color: #fff;
         }
@@ -91,9 +91,9 @@ the trace process after the user clicks on the trace button.
 
       <p class="error">{{error}}</p>
 
-      <paper-button affirmative raised autofocus disabled$="{{error}}"
+      <paper-button dialog-confirm raised autofocus disabled$="{{error}}"
                     on-click="onSendToTrybot">Send to perf try bot</paper-button>
-      <paper-button dismissive raised>Close</paper-button>
+      <paper-button dialog-dismiss raised>Close</paper-button>
 
       <template is="dom-if" if="{{loading}}">
         <div id="loading">