MD Settings: Restore focus after exiting various subpages.

chrome/browser/resources/settings/appearance_page/appearance_page.js

Index: chrome/browser/resources/settings/appearance_page/appearance_page.js
diff --git a/chrome/browser/resources/settings/appearance_page/appearance_page.js b/chrome/browser/resources/settings/appearance_page/appearance_page.js
index 5518952b4fe43645608fedee8e977173a14652c7..9a71e358ca9fc8001fbb6f447af490010b7c57f1 100644
--- a/chrome/browser/resources/settings/appearance_page/appearance_page.js
+++ b/chrome/browser/resources/settings/appearance_page/appearance_page.js
@@ -89,6 +89,9 @@ Polymer({
       type: Boolean,
       value: false,  // Can only be true on Linux, but value exists everywhere.
     },
+
+    /** @private {?Map<string, string>} */
+    focusConfig_: Object,
   },
 
   /** @private {?settings.AppearanceBrowserProxy} */
@@ -117,6 +120,11 @@ Polymer({
     this.browserProxy_.getDefaultZoom().then(function(zoom) {
       this.defaultZoom_ = zoom;
     }.bind(this));
+
+    this.focusConfig_ = new Map();
+    this.focusConfig_.set(
+        settings.Route.FONTS.path,
+        '#customize-fonts-subpage-trigger .subpage-arrow');
   },
 
   /**