downloads: add the ability to undo download removal.

chrome/browser/resources/downloads/downloads.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.
 
 // TODO(jhawkins): Use hidden instead of showInline* and display:none.
 
 /**
  * The type of the download object. The definition is based on
  * chrome/browser/ui/webui/downloads_dom_handler.cc:CreateDownloadItemValue()
  * @typedef {{by_ext_id: (string|undefined),
@@ skipping 11 matching lines @@
  *            progress_status_text: (string|undefined),
  *            received: (number|undefined),
  *            resume: boolean,
  *            retry: boolean,
  *            since_string: string,
  *            started: number,
  *            state: string,
  *            total: number,
  *            url: string}}
  */
-var BackendDownloadObject;
+var DownloadItem;
 
 /**
  * Sets the display style of a node.
  * @param {!Element} node The target element to show or hide.
  * @param {boolean} isShow Should the target element be visible.
  */
 function showInline(node, isShow) {
   node.style.display = isShow ? 'inline' : 'none';
 }
 
@@ skipping 58 matching lines @@
   this.iconLoadQueue_ = [];
   this.isIconLoading_ = false;
 
   this.progressForeground1_ = new Image();
   this.progressForeground1_.src =
     'chrome://theme/IDR_DOWNLOAD_PROGRESS_FOREGROUND_32@1x';
   this.progressForeground2_ = new Image();
   this.progressForeground2_.src =
     'chrome://theme/IDR_DOWNLOAD_PROGRESS_FOREGROUND_32@2x';
 
-  window.addEventListener('keydown', this.onKeyDown_.bind(this));
+  cr.ui.decorate('command', cr.ui.Command);
+  document.addEventListener('canExecute', this.onCanExecute_.bind(this));
+  document.addEventListener('command', this.onCommand_.bind(this));
 
   this.updateResults();
 }
 
 /**
  * Called when a download has been updated or added.
- * @param {BackendDownloadObject} download A backend download object
+ * @param {DownloadItem} download Information about a download.
  */
 Downloads.prototype.updated = function(download) {
   var id = download.id;
-  if (!!this.downloads_[id]) {
+  if (this.downloads_[id]) {
     this.downloads_[id].update(download);
   } else {
     this.downloads_[id] = new Download(download);
     // We get downloads in display order, so we don't have to worry about
     // maintaining correct order - we can assume that any downloads not in
     // display order are new ones and so we can add them to the top of the
     // list.
     if (download.started > this.newestTime_) {
       this.node_.insertBefore(this.downloads_[id].node, this.node_.firstChild);
       this.newestTime_ = download.started;
@@ skipping 54 matching lines @@
  * Called whenever the downloads lists items have changed (either by being
  * updated, added, or removed).
  * @private
  */
 Downloads.prototype.onDownloadListChanged_ = function() {
   // Update the date visibility in our nodes so that no date is repeated.
   var dateContainers = document.getElementsByClassName('date-container');
   var displayed = {};
   for (var i = 0, container; container = dateContainers[i]; i++) {
     var dateString = container.getElementsByClassName('date')[0].innerHTML;
-    if (!!displayed[dateString]) {
+    if (displayed[dateString]) {
       container.style.display = 'none';
     } else {
       displayed[dateString] = true;
       container.style.display = 'block';
     }
   }
 
   this.updateResults();
 };
 
@@ skipping 66 matching lines @@
   // downloads having been inserted.  So check only for new downloads in
   // deciding whether to update.
   for (var i = 0; i < downloads.length; i++) {
     if (!this.downloads_[downloads[i].id])
       return true;
   }
   return false;
 };
 
 /**
- * Handles shortcut keys.
- * @param {Event} evt The keyboard event.
+ * @param {Event} e
  * @private
  */
-Downloads.prototype.onKeyDown_ = function(evt) {
-  var keyEvt = /** @type {KeyboardEvent} */(evt);
-  if (keyEvt.keyCode == 67 && keyEvt.altKey) {  // alt + c.
+Downloads.prototype.onCanExecute_ = function(e) {
+  e = /** @type {cr.ui.CanExecuteEvent} */(e);
+  e.canExecute = document.activeElement != $('term');
+};
+
+/**
+ * @param {Event} e
+ * @private
+ */
+Downloads.prototype.onCommand_ = function(e) {
+  if (e.command.id == 'undo-command')
+    chrome.send('undoRemove');
+  else if (e.command.id == 'clear-all-command')
     clearAll();
-    keyEvt.preventDefault();
-  }
 };
 
 ///////////////////////////////////////////////////////////////////////////////
 // Download
 /**
  * A download and the DOM representation for that download.
- * @param {BackendDownloadObject} download A backend download object
+ * @param {DownloadItem} download Info about the download.
  * @constructor
  */
 function Download(download) {
   // Create DOM
   this.node = createElementWithClassName(
       'div', 'download' + (download.otr ? ' otr' : ''));
 
   // Dates
   this.dateContainer_ = createElementWithClassName('div', 'date-container');
   this.node.appendChild(this.dateContainer_);
@@ skipping 205 matching lines @@
 
 // Listens for when device-pixel-ratio changes between any zoom level.
 [0.3, 0.4, 0.6, 0.7, 0.8, 0.95, 1.05, 1.2, 1.4, 1.6, 1.9, 2.2, 2.7, 3.5, 4.5
 ].forEach(function(scale) {
   var media = '(-webkit-min-device-pixel-ratio:' + scale + ')';
   window.matchMedia(media).addListener(computeDownloadProgress);
 });
 
 /**
  * Updates the download to reflect new data.
- * @param {BackendDownloadObject} download A backend download object
+ * @param {DownloadItem} download Updated info about this download.
  */
 Download.prototype.update = function(download) {
   this.id_ = download.id;
   this.filePath_ = download.file_path;
   this.fileUrl_ = download.file_url;
   this.fileName_ = download.file_name;
   this.url_ = download.url;
   this.state_ = download.state;
   this.fileExternallyRemoved_ = download.file_externally_removed;
   this.dangerType_ = download.danger_type;
@@ skipping 239 matching lines @@
 };
 
 /**
  * Tells the backend to initiate a drag, allowing users to drag
  * files from the download page and have them appear as native file
  * drags.
  * @return {boolean} Returns false to prevent the default action.
  * @private
  */
 Download.prototype.drag_ = function() {
-  chrome.send('drag', [this.id_.toString()]);

[Dan Beam, 2014/11/13 02:51:16]

i don't think that |this.id_| being a double (a number in javascript) was
actually safe.  i've converted it to a string and am handling it slightly
differently in C++ to accommodate.  it seems unlikely that anybody would hit
this in practice, though...

+  chrome.send('drag', [this.id_]);
   return false;
 };
 
 /**
  * Tells the backend to open this file.
  * @return {boolean} Returns false to prevent the default action.
  * @private
  */
 Download.prototype.openFile_ = function() {
-  chrome.send('openFile', [this.id_.toString()]);
+  chrome.send('openFile', [this.id_]);
   return false;
 };
 
 /**
  * Tells the backend that the user chose to save a dangerous file.
  * @return {boolean} Returns false to prevent the default action.
  * @private
  */
 Download.prototype.saveDangerous_ = function() {
-  chrome.send('saveDangerous', [this.id_.toString()]);
+  chrome.send('saveDangerous', [this.id_]);
   return false;
 };
 
 /**
  * Tells the backend that the user chose to discard a dangerous file.
  * @return {boolean} Returns false to prevent the default action.
  * @private
  */
 Download.prototype.discardDangerous_ = function() {
-  chrome.send('discardDangerous', [this.id_.toString()]);
+  chrome.send('discardDangerous', [this.id_]);
   downloads.remove(this.id_);
   return false;
 };
 
 /**
  * Tells the backend to show the file in explorer.
  * @return {boolean} Returns false to prevent the default action.
  * @private
  */
 Download.prototype.show_ = function() {
-  chrome.send('show', [this.id_.toString()]);
+  chrome.send('show', [this.id_]);
   return false;
 };
 
 /**
  * Tells the backend to pause this download.
  * @return {boolean} Returns false to prevent the default action.
  * @private
  */
 Download.prototype.pause_ = function() {
-  chrome.send('pause', [this.id_.toString()]);
+  chrome.send('pause', [this.id_]);
   return false;
 };
 
 /**
  * Tells the backend to resume this download.
  * @return {boolean} Returns false to prevent the default action.
  * @private
  */
 Download.prototype.resume_ = function() {
-  chrome.send('resume', [this.id_.toString()]);
+  chrome.send('resume', [this.id_]);
   return false;
 };
 
 /**
  * Tells the backend to remove this download from history and download shelf.
  * @return {boolean} Returns false to prevent the default action.
  * @private
  */
- Download.prototype.remove_ = function() {
-   if (loadTimeData.getBoolean('allow_deleting_history')) {
-    chrome.send('remove', [this.id_.toString()]);
-  }
+Download.prototype.remove_ = function() {
+  if (loadTimeData.getBoolean('allow_deleting_history'))
+    chrome.send('remove', [this.id_]);
   return false;
 };
 
 /**
  * Tells the backend to cancel this download.
  * @return {boolean} Returns false to prevent the default action.
  * @private
  */
 Download.prototype.cancel_ = function() {
-  chrome.send('cancel', [this.id_.toString()]);
+  chrome.send('cancel', [this.id_]);
   return false;
 };
 
 ///////////////////////////////////////////////////////////////////////////////
 // Page:
 var downloads, resultsTimeout;
 
 // TODO(benjhayden): Rename Downloads to DownloadManager, downloads to
 // downloadManager or theDownloadManager or DownloadManager.get() to prevent
 // confusing Downloads with Download.
@@ skipping 111 matching lines @@
     if (Date.now() - start > 50) {
       clearTimeout(resultsTimeout);
       resultsTimeout = setTimeout(tryDownloadUpdatedPeriodically, 5);
       break;
     }
   }
 }
 
 // Add handlers to HTML elements.
 window.addEventListener('DOMContentLoaded', load);