[Media Router WebUI] Set titles for buttons.

chrome/browser/resources/media_router/elements/media_router_header/media_router_header.js

Index: chrome/browser/resources/media_router/elements/media_router_header/media_router_header.js
diff --git a/chrome/browser/resources/media_router/elements/media_router_header/media_router_header.js b/chrome/browser/resources/media_router/elements/media_router_header/media_router_header.js
index 0eb1e45dae8b6e1a73ff005972e09d4b3a5b1d1d..2815bf5adc93b0a2c4ee75f5f338cc869fdf657a 100644
--- a/chrome/browser/resources/media_router/elements/media_router_header/media_router_header.js
+++ b/chrome/browser/resources/media_router/elements/media_router_header/media_router_header.js
@@ -27,6 +27,42 @@ Polymer({
     },
 
     /**
+     * Title text for the back button.
+     * @private {string}
+     */
+    backButtonTitle_: {
+      type: String,
+      readOnly: true,
+      value: function() {
+        return loadTimeData.getString('backButtonTitle');
+      },
+    },
+
+    /**
+     * Title text for the close button.
+     * @private {string}
+     */
+    closeButtonTitle_: {
+      type: String,
+      readOnly: true,
+      value: function() {
+        return loadTimeData.getString('closeButtonTitle');
+      },
+    },
+
+    /**
+     * Title text for the drop down button.
+     * @private {string}
+     */
+    dropDownButtonTitle_: {
+      type: String,
+      readOnly: true,
+      value: function() {
+        return loadTimeData.getString('dropDownButtonTitle');
+      },
+    },
+
+    /**
      * The header text to show.
      * @type {string}
      */