Reverting this revert, since it does not seem to have caused the breakage.

chrome/browser/resources/options/language_options.css

 .language-options {
   display: -webkit-box;
   margin: 10px 0;
 }
 
 .language-options-lower-left button,
 .language-options-right button {
   min-width: 70px;
 }
 
@@ skipping 21 matching lines @@
   height: 400px;
 }
 
 .language-options-left {
   -webkit-box-orient: vertical;
   display: -webkit-box;
   background-color: #ebeff9;
   width: 300px;
 }
 
+/* On OS X we use the native OS spellchecker, so don't display the dictionary */
+/* pane. */
+html[os=mac] .language-options-left {
+ background-color: white;
+}
+
+html[os=mac] .language-options-right {
+ visibility: hidden;
+}
+
 .language-options-lower-left {
   -webkit-box-flex: 0;
   -webkit-padding-start: 12px;
   padding-bottom: 10px;
 }
 
 .language-options-right {
   /* To share the center line with the left pane. */
   -webkit-margin-start: -1px;
   width: 360px;
@@ skipping 168 matching lines @@
 
 button[disabled].text-button,
 button[disabled].text-button:active,
 button[disabled].text-button:focus,
 button[disabled].text-button:hover {
   -webkit-box-shadow: none;
   background: transparent none;
   border-color: transparent;
   color: #AAA;
 }