Postpone connecting to GData even more, provide progress indication.

chrome/browser/resources/file_manager/js/directory_model.js

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // If directory files changes too often, don't rescan directory more than once
 // per specified interval
 const SIMULTANEOUS_RESCAN_INTERVAL = 1000;
 
 /**
  * Data model of the file manager.
@@ skipping 736 matching lines @@
     function onCacheDone() {
       waitCount--;
       // If all caching functions finished synchronously or entries.length = 0
       // call the callback synchronously.
       if (waitCount == 0)
         setTimeout(callback, 0);
     }
   },
 
   /**
-   * Get root entries asynchronously. Invokes callback
-   * when have finished.
+   * Get root entries asynchronously.
+   * @param {function(Array.<Entry>} callback Called when roots are resolved.
+   * @param {boolean} resolveGData See comment for updateRoots.
    */
-  resolveRoots_: function(callback) {
+  resolveRoots_: function(callback, resolveGData) {
     var groups = {
       downloads: null,
       archives: null,
       removables: null,
       gdata: null
     };
 
     metrics.startInterval('Load.Roots');
     function done() {
       for (var i in groups)
@@ skipping 29 matching lines @@
       console.log(entry);
       self.unmountedGDataEntry_ = null;
       groups.gdata = [entry];
       done();
     }
 
     function onGDataError(error) {
       console.log('onGDataError');
       console.log(error);
       self.unmountedGDataEntry_ = {
+        unmounted: true,  // Clients use this field to distinguish a fake root.
+        toURL: function() { return '' },
         fullPath: '/' + DirectoryModel.GDATA_DIRECTORY
       };
       groups.gdata = [self.unmountedGDataEntry_];
       done();
     }
 
     var root = this.root_;
     root.getDirectory(DirectoryModel.DOWNLOADS_DIRECTORY, { create: false },
                       onDownloads, onDownloadsError);
     util.readDirectory(root, DirectoryModel.ARCHIVE_DIRECTORY,
                        append.bind(this, 'archives'));
     util.readDirectory(root, DirectoryModel.REMOVABLE_DIRECTORY,
                        append.bind(this, 'removables'));
     if (this.showGData_) {
-      root.getDirectory(DirectoryModel.GDATA_DIRECTORY, { create: false },
-                        onGData, onGDataError);
+      if (resolveGData) {
+        root.getDirectory(DirectoryModel.GDATA_DIRECTORY, { create: false },
+                          onGData, onGDataError);
+      } else {
+        onGDataError('lazy mount');
+      }
     } else {
       groups.gdata = [];
     }
   },
 
-  updateRoots: function(opt_callback) {
+  /**
+  * @param {function} opt_callback Called when all roots are resolved.
+  * @param {boolean} opt_resolveGData If true GData should be resolved for real,
+  *                                   If false a stub entry should be created.
+  */
+  updateRoots: function(opt_callback, opt_resolveGData) {
     console.log('directoryModel_.updateRoots');
     var self = this;
     this.resolveRoots_(function(rootEntries) {
       console.log('rootsList_ = ');
       console.log(self.rootsList_);
       var dm = self.rootsList_;
       var args = [0, dm.length].concat(rootEntries);
       dm.splice.apply(dm, args);
 
       self.updateRootsListSelection_();
 
       if (opt_callback)
         opt_callback();
-    });
+    }, opt_resolveGData);
   },
 
   onRootsSelectionChanged_: function(event) {
     var root = this.rootsList.item(this.rootsListSelection.selectedIndex);
     var current = this.currentEntry.fullPath;
     if (root && this.rootPath != root.fullPath)
       this.changeDirectory(root.fullPath);
   },
 
   updateRootsListSelection_: function() {
@@ skipping 134 matching lines @@
 
   recordMetrics_: function() {
     metrics.recordInterval('DirectoryScan');
     if (this.dir_.fullPath ==
         '/' + DirectoryModel.DOWNLOADS_DIRECTORY) {
       metrics.recordMediumCount("DownloadsCount", this.list_.length);
     }
   }
 };