Fix display and progressive disclosure for multi-line values in about:policy.

chrome/browser/resources/policy.css

 body {
   color: black;
   cursor: default;
   font-family: Arial, sans-serif;
   font-size: 14px;
   margin: 0 10px;
   min-width: 47em;
 }
 
 button {
@@ skipping 118 matching lines @@
   border-collapse: collapse;
 }
 
 #policy-table th {
   background-color: #dadadd;
   padding: 10px;
 }
 
 #policy-table td {
   background-color: #eaeef3;
-  overflow: hidden;
   padding: 10px;
-  text-overflow: ellipsis;
+  position: relative;
+  vertical-align: top;
   width: 20%;
 }
 
-.toggler {
-  color: #808080;
-  cursor: pointer;
+.text-collapsed {
+  bottom: 0;
+  left: 0;
+  margin: 10px;
+  overflow: hidden;
+  position: absolute;
+  right: 0;
+  top: 0;
 }
 
-.collapsed {
+.text-cell {
   overflow: hidden;
+}
+
+.text-collapsed .text-cell {
   text-overflow: ellipsis;
+}
+
+.text-expanded .text-cell {
+  overflow: visible;
+  word-wrap: break-word;
+}
+
+.text-collapsed .text-value {
   white-space: nowrap;
 }
 
-.expanded {
-  overflow: visible;
-  word-wrap: break-word;
+.text-expanded .text-value {
+  white-space: pre-wrap;
 }
+
+.toggler {
+  float: right;
+  margin-left: .5em !important;
+}