Hotword Audio Verification App: UI polishes.

chrome/browser/resources/hotword_audio_verification/style.css

Index: chrome/browser/resources/hotword_audio_verification/style.css
diff --git a/chrome/browser/resources/hotword_audio_verification/style.css b/chrome/browser/resources/hotword_audio_verification/style.css
index 8825dd75b323cfb61be19f610bae56d5c8698cae..35e849a034f01ab3c22ce751e73c9064a67c9a4c 100644
--- a/chrome/browser/resources/hotword_audio_verification/style.css
+++ b/chrome/browser/resources/hotword_audio_verification/style.css
@@ -76,8 +76,9 @@ div.content {
 }
 
 
-button.grayed-out {
+.buttonbar button.grayed-out {
   color: rgba(0, 0, 0, .28);
+  text-transform: none;
 }
 
 .col-3 {
@@ -180,7 +181,16 @@ button.primary {
   color: rgb(213, 0, 0);
 }
 
+@-webkit-keyframes rotate {
+  from { -webkit-transform: rotate(0); }
+  to { -webkit-transform: rotate(359deg); }
+}
+
 .train.listening .icon {
+  -webkit-animation-duration: 2s;
+  -webkit-animation-iteration-count: infinite;
+  -webkit-animation-name: rotate;
+  -webkit-animation-timing-function: linear;
   background: url(../images/placeholder-loader-1x.png) no-repeat;
 }