dom-ui settings: enable languages & spell checker settings for all platforms....

chrome/browser/resources/options/language_options.css

 .language-options {
   display: -webkit-box;
   margin: 15px;
 }
 
 .language-options button {
   min-width: 70px;
 }
 
 .language-options h3 {
   -webkit-margin-start: 12px;
-  font-size: 75%;
+  font-size: 100%;
   font-weight: bold;
   margin-top: 12px;
 }
 
 .language-options label {
   display: block;
 }
 
 .language-options-contents  {
   -webkit-padding-start: 12px;
@@ skipping 43 matching lines @@
   display: block;
   -webkit-margin-start: 20px;
 }
 
 #language-options-input-method-list label {
   margin: 4px 0;
 }
 
 #language-options-list {
   -webkit-box-flex: 1;
-  padding: 0;
+  padding: 1px 0 0;
   width: 100%;
 }
 
 #language-options-list li {
   -webkit-padding-start: 12px;
   padding-top: 2px;
   padding-bottom: 2px;
 }
 
 #language-options-ui-restart-button {
   margin-top: 12px;
 }
 
-#add-language-overlay-language-list {
+#add-language-overlay-language-list[os=chromeos] {
   -webkit-column-count: 2;
   -webkit-column-gap: 20px;
 }
 
-#add-language-overlay-cancel-button {
+#add-language-overlay-cancel-button[os=chromeos] {
   /* Place the button in the center. */
   display: block;
   margin: auto;
   margin-top: 15px;
 }
 
-#add-language-overlay-page {
+#add-language-overlay-page[os=chromeos] {
   width: 800px;
 }
 
-#add-language-overlay-page button {
+#add-language-overlay-page[os=chromeos] button {
   padding: 0;
   text-align: left;
 }
 
-#add-language-overlay-page ul {
+#add-language-overlay-page[os=chromeos] ul {
   padding: 0;
   margin: 0;
 }
+
 /* TODO(kochi): This is temporary copy from new_new_tab.css */
 /* Notification */
 
 #notification {
   position: relative;
   background-color: hsl(52, 100%, 80%);
   border: 1px solid rgb(211, 211, 211);
   border-radius: 6px;
   padding: 7px 15px;
   white-space: nowrap;
@@ skipping 34 matching lines @@
 }
 
 #notification .link-color {
   color: rgb(0, 102, 204);
 }
 
 #chewing-max-chi-symbol-len {
   width: 100px;
   height: 30%;
 }