Switch dashboard to new flexbox.

dashboard/dashboard/elements/chart-container.html

Index: dashboard/dashboard/elements/chart-container.html
diff --git a/dashboard/dashboard/elements/chart-container.html b/dashboard/dashboard/elements/chart-container.html
index 402fc341de7b53891a1eb04dbd606266671a7d10..017ab5443cb70ed8bfb358b2ff9d07692c1783ac 100644
--- a/dashboard/dashboard/elements/chart-container.html
+++ b/dashboard/dashboard/elements/chart-container.html
@@ -36,11 +36,8 @@ triaging functionality in the chart.
     #container {
       width: 100%;
       display: flex;
-      display: -webkit-flex;
       flex-direction: column;
-      -webkit-flex-direction: column;
       align-items: center;
-      -webkit-align-items: center;
       position: relative;
       min-width: 845px;  /* Minimum width of plot plus width of chart-legend. */
     }
@@ -51,7 +48,6 @@ triaging functionality in the chart.
 
     #horizontal {
       display: flex;
-      display: -webkit-flex;
       width: 100%;
       position: relative;
     }
@@ -69,15 +65,12 @@ triaging functionality in the chart.
     }
 
     #plots-container {
-      -webkit-flex-grow: 1;
       flex-grow: 1;
-      display: -webkit-flex;
+      display: flex;
       flex-direction: column;
-      -webkit-flex-direction: column;
     }
 
     #plot {
-      -webkit-flex-grow: 1;
       flex-grow: 1;
       height: 240px;
       min-width: 500px;
@@ -111,11 +104,8 @@ triaging functionality in the chart.
       width: 100%;
       height: 100%;
       display: flex;
-      display: -webkit-flex;
       align-items: center;
-      -webkit-align-items: center;
       justify-content: center;
-      -webkit-justify-content: center;
     }
 
     #alert-icon-container {