drive: Stop making multiple GetAppList() requests from DriveAppRegistry

chrome/browser/chromeos/drive/drive_app_registry.cc

 // 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.
 
 #include "chrome/browser/chromeos/drive/drive_app_registry.h"
 
 #include <algorithm>
 #include <string>
 #include <utility>
 #include <vector>
@@ skipping 77 matching lines @@
       is_primary_selector(is_primary_selector) {
 }
 
 DriveAppRegistry::DriveAppFileSelector::~DriveAppFileSelector() {
 }
 
 // DriveAppRegistry implementation.
 
 DriveAppRegistry::DriveAppRegistry(JobScheduler* scheduler)
     : scheduler_(scheduler),
+      is_updating_(false),
       weak_ptr_factory_(this) {
 }
 
 DriveAppRegistry::~DriveAppRegistry() {
   STLDeleteValues(&app_extension_map_);
   STLDeleteValues(&app_mimetypes_map_);
 }
 
 void DriveAppRegistry::GetAppsForFile(
     const base::FilePath& file_path,
@@ skipping 22 matching lines @@
     if (inserted_app_ids.find(it->second->app_id) == inserted_app_ids.end()) {
       inserted_app_ids.insert(it->second->app_id);
       apps->push_back(it->second);
     }
   }
 }
 
 void DriveAppRegistry::Update() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
+  if (is_updating_)  // There is already an update in progress.
+    return;
+
+  is_updating_ = true;
+
   scheduler_->GetAppList(
       base::Bind(&DriveAppRegistry::UpdateAfterGetAppList,
                  weak_ptr_factory_.GetWeakPtr()));
 }
 
 void DriveAppRegistry::UpdateAfterGetAppList(
     google_apis::GDataErrorCode gdata_error,
     scoped_ptr<google_apis::AppList> app_list) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
+  DCHECK(is_updating_);
+  is_updating_ = false;
+
   FileError error = GDataToFileError(gdata_error);
   if (error != FILE_ERROR_OK) {
     // Failed to fetch the data from the server. We can do nothing here.
     return;
   }
 
   DCHECK(app_list);
 
   url_to_name_map_.clear();
   STLDeleteValues(&app_extension_map_);
@@ skipping 106 matching lines @@
                          web_app->app_icons,
                          web_app->document_icons,
                          web_store_id,
                          UTF8ToUTF16(product_iter->second),   // app name.
                          web_app->object_type,
                          web_app->is_primary_selector)));
   }
 }
 
 }  // namespace drive