MD Settings: Add route for the Import Data dialog at /importData.

chrome/browser/resources/settings/people_page/people_page.js

Index: chrome/browser/resources/settings/people_page/people_page.js
diff --git a/chrome/browser/resources/settings/people_page/people_page.js b/chrome/browser/resources/settings/people_page/people_page.js
index db48750dc6c900c3dca551c2647d0c57f3e51d8c..eee145ccd8dffe61887ffc0c7de74dac01f4f051 100644
--- a/chrome/browser/resources/settings/people_page/people_page.js
+++ b/chrome/browser/resources/settings/people_page/people_page.js
@@ -150,6 +150,9 @@ Polymer({
 
   /** @protected */
   currentRouteChanged: function() {
+    this.showImportDataDialog_ =
+        settings.getCurrentRoute() == settings.Route.IMPORT_DATA;
+
     if (settings.getCurrentRoute() == settings.Route.SIGN_OUT) {
       // If the sync status has not been fetched yet, optimistically display
       // the disconnect dialog. There is another check when the sync status is
@@ -359,12 +362,12 @@ Polymer({
 
   /** @private */
   onImportDataTap_: function() {
-    this.showImportDataDialog_ = true;
+    settings.navigateTo(settings.Route.IMPORT_DATA);
   },
 
   /** @private */
   onImportDataDialogClosed_: function() {
-    this.showImportDataDialog_ = false;
+    settings.navigateToPreviousRoute();
   },
 </if>