Add window buttons (close and maximize) to the Files.app's new UI.

chrome/browser/resources/file_manager/js/file_tasks.js

Index: chrome/browser/resources/file_manager/js/file_tasks.js
diff --git a/chrome/browser/resources/file_manager/js/file_tasks.js b/chrome/browser/resources/file_manager/js/file_tasks.js
index 9ab11763276ced18effca213ec8d02b34befedd9..cd6964934b11d6403a0033955a9f3b0339d0f3fd 100644
--- a/chrome/browser/resources/file_manager/js/file_tasks.js
+++ b/chrome/browser/resources/file_manager/js/file_tasks.js
@@ -507,7 +507,7 @@ FileTasks.prototype.openGalleryInternal_ = function(urls) {
   // changes in the Gallery and popped when the Gallery is closed.
   util.updateAppState(false /*push*/);
 
-  var onClose = function(selectedUrls) {
+  var onBack = function(selectedUrls) {
     fm.directoryModel_.selectUrls(selectedUrls);
     if (util.platform.v2()) {
       fm.closeFilePopup_();  // Will call Gallery.unload.
@@ -519,6 +519,14 @@ FileTasks.prototype.openGalleryInternal_ = function(urls) {
     }
   };
 
+  var onClose = function() {
+    fm.onClose();
+  };
+
+  var onMaximize = function() {
+    fm.onMaximize();
+  };
+
   galleryFrame.onload = function() {
     fm.show_();
     galleryFrame.contentWindow.ImageUtil.metrics = metrics;
@@ -545,7 +553,9 @@ FileTasks.prototype.openGalleryInternal_ = function(urls) {
       searchResults: fm.directoryModel_.isSearching(),
       metadataCache: fm.metadataCache_,
       pageState: this.params_,
+      onBack: onBack,
       onClose: onClose,
+      onMaximize: onMaximize,
       onThumbnailError: function(imageURL) {
         fm.metadataCache_.refreshFileMetadata(imageURL);
       },