Print Preview: Display a throbber when the user requests the system print

chrome/browser/resources/print_preview/print_preview.css

Index: chrome/browser/resources/print_preview/print_preview.css
diff --git a/chrome/browser/resources/print_preview/print_preview.css b/chrome/browser/resources/print_preview/print_preview.css
index 183fc268a4a07f08f73d2477d055ba438e083213..bb08a8e2c302a63c808fdec58c82ad1efee5cf8c 100644
--- a/chrome/browser/resources/print_preview/print_preview.css
+++ b/chrome/browser/resources/print_preview/print_preview.css
@@ -35,7 +35,7 @@ body #main::after {
 
 /* Layout: Sidebar */
 
-.sidebar {
+#sidebar {
   -webkit-user-select: none;
   border: 1px solid #a0a0a0;
   background: white;
@@ -47,11 +47,11 @@ body #main::after {
   z-index: 2000;
 }
 
-.sidebar header {
+#sidebar header {
   width: 310px;
 }
 
-.sidebar header > h1 {
+#sidebar header > h1 {
   -webkit-padding-start: 16px;
 }
 
@@ -176,7 +176,11 @@ hr.invisible {
   display: none;
 }
 
-a {
+/* TODO(jhawkins): Remove this specialization once all WebUI shares the same
+ * link-button styling.
+ */
+#system-dialog-link {
+  -webkit-padding-start: 0;
   -webkit-transition: text-shadow 150ms;
   color: #4080fa;
   outline: 0;
@@ -184,16 +188,16 @@ a {
   text-shadow: 0 0 1px white;
 }
 
-a:hover {
+#system-dialog-link:hover {
   text-shadow: 0 0 1px rgba(85, 143, 250, .75);
 }
 
-a:active {
+#system-dialog-link:active {
   color: #4080fa;
   text-shadow: 0 0 1px rgba(64, 128, 250, 1);
 }
 
-a:focus {
+#system-dialog-link:focus {
   -webkit-transition: border-color 200ms;
   border-radius: 2px;
   border: 1px solid rgba(85, 143, 250, .8);
@@ -201,6 +205,12 @@ a:focus {
   padding: 1px 4px;
 }
 
+#system-dialog-link:disabled {
+  color: rgba(0, 0, 0, .5);
+  cursor: default;
+  text-shadow: none;
+}
+
 strong {
   font-weight: 600;
 }
@@ -759,3 +769,7 @@ html[dir='rtl'] .messages {
 input[disabled] + label {
   color: gray;
 }
+
+#error-action-area {
+  margin-top: 10px;
+}