Support for ng-message-exp directive.

src/components/input/input-theme.scss

@@ -17,7 +17,8 @@ md-input-container.md-THEME_NAME-theme {
   }
 
   ng-messages,
-  [ng-message], [data-ng-message], [x-ng-message] {
+  [ng-message], [data-ng-message], [x-ng-message],
+  [ng-message-exp], [data-ng-message-exp], [x-ng-message-exp] {
     color: '{{warn-500}}'
   }
 
@@ -65,6 +66,8 @@ md-input-container.md-THEME_NAME-theme {
     }
     ng-message, data-ng-message, x-ng-message,
     [ng-message], [data-ng-message], [x-ng-message],
+    ng-message-exp, data-ng-message-exp, x-ng-message-exp,
+    [ng-message-exp], [data-ng-message-exp], [x-ng-message-exp],
     .md-char-counter {
       color: '{{warn-500}}';
     }

src/components/input/input.scss

@@ -163,6 +163,8 @@ md-input-container {
   }
   ng-message, data-ng-message, x-ng-message,
   [ng-message], [data-ng-message], [x-ng-message],
+  ng-message-exp, data-ng-message-exp, x-ng-message-exp,
+  [ng-message-exp], [data-ng-message-exp], [x-ng-message-exp],
   .md-char-counter {
     //-webkit-font-smoothing: antialiased;
     position: absolute;