downloads: add the ability to undo download removal.

chrome/browser/ui/webui/downloads_dom_handler.cc

Index: chrome/browser/ui/webui/downloads_dom_handler.cc
diff --git a/chrome/browser/ui/webui/downloads_dom_handler.cc b/chrome/browser/ui/webui/downloads_dom_handler.cc
index f347ba33b455b8cfb0f31555b804c19ea5752ca5..2ee32bf88ae1ac8cf25f9d89b8a3e2647c4003a9 100644
--- a/chrome/browser/ui/webui/downloads_dom_handler.cc
+++ b/chrome/browser/ui/webui/downloads_dom_handler.cc
@@ -16,6 +16,7 @@
 #include "base/metrics/field_trial.h"
 #include "base/metrics/histogram.h"
 #include "base/prefs/pref_service.h"
+#include "base/strings/string_number_conversions.h"
 #include "base/strings/string_piece.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/threading/thread.h"
@@ -131,7 +132,7 @@ base::DictionaryValue* CreateDownloadItemValue(
           download_item->GetStartTime(), NULL));
   file_value->SetString(
       "date_string", base::TimeFormatShortDate(download_item->GetStartTime()));
-  file_value->SetInteger("id", download_item->GetId());
+  file_value->SetString("id", base::Uint64ToString(download_item->GetId()));
 
   base::FilePath download_path(download_item->GetTargetFilePath());
   file_value->Set("file_path", base::CreateFilePathValue(download_path));
@@ -156,7 +157,7 @@ base::DictionaryValue* CreateDownloadItemValue(
 
   // Keep file names as LTR.
   base::string16 file_name =
-    download_item->GetFileNameToReportUser().LossyDisplayName();
+      download_item->GetFileNameToReportUser().LossyDisplayName();
   file_name = base::i18n::GetDisplayStringInLTRDirectionality(file_name);
   file_value->SetString("file_name", file_name);
   file_value->SetString("url", download_item->GetURL().spec());
@@ -229,8 +230,9 @@ base::DictionaryValue* CreateDownloadItemValue(
       file_value->SetString("state", "COMPLETE");
       break;
 
+    case content::DownloadItem::REMOVED:
     case content::DownloadItem::MAX_DOWNLOAD_STATE:
-      NOTREACHED() << "state undefined";
+      NOTREACHED();
   }
 
   return file_value;
@@ -240,6 +242,7 @@ base::DictionaryValue* CreateDownloadItemValue(
 bool IsDownloadDisplayable(const content::DownloadItem& item) {
   return (!download_crx_util::IsExtensionDownload(item) &&
           !item.IsTemporary() &&
+          item.GetState() != content::DownloadItem::REMOVED &&
           !item.GetFileNameToReportUser().empty() &&
           !item.GetTargetFilePath().empty());
 }
@@ -262,6 +265,14 @@ DownloadsDOMHandler::DownloadsDOMHandler(content::DownloadManager* dlm)
 }
 
 DownloadsDOMHandler::~DownloadsDOMHandler() {
+  while (!removed_ids_.empty()) {
+    uint32 remove_id = removed_ids_.back();
+    removed_ids_.pop_back();
+
+    content::DownloadItem* download = GetDownloadById(remove_id);
+    if (download)
+      download->Remove();
+  }
 }
 
 // DownloadsDOMHandler, public: -----------------------------------------------
@@ -310,6 +321,9 @@ void DownloadsDOMHandler::RegisterMessages() {
   web_ui()->RegisterMessageCallback("openDownloadsFolder",
       base::Bind(&DownloadsDOMHandler::HandleOpenDownloadsFolder,
                  weak_ptr_factory_.GetWeakPtr()));
+  web_ui()->RegisterMessageCallback("undoRemove",
+      base::Bind(&DownloadsDOMHandler::HandleUndoRemove,
+                 weak_ptr_factory_.GetWeakPtr()));
 }
 
 void DownloadsDOMHandler::OnDownloadCreated(
@@ -340,6 +354,8 @@ void DownloadsDOMHandler::OnDownloadUpdated(
         (original_notifier_.get() &&
           (manager == main_notifier_.GetManager()))));
     CallDownloadUpdated(results_value);
+  } else if (download_item->GetState() == content::DownloadItem::REMOVED) {
+    ScheduleSendCurrentDownloads();
   }
 }
 
@@ -438,8 +454,10 @@ void DownloadsDOMHandler::HandleRemove(const base::ListValue* args) {
 
   CountDownloadsDOMEvents(DOWNLOADS_DOM_EVENT_REMOVE);
   content::DownloadItem* file = GetDownloadByValue(args);
-  if (file)
-    file->Remove();
+  if (file) {
+    removed_ids_.push_back(file->GetId());
+    file->MarkRemoved();
+  }
 }
 
 void DownloadsDOMHandler::HandleCancel(const base::ListValue* args) {
@@ -480,6 +498,18 @@ void DownloadsDOMHandler::HandleOpenDownloadsFolder(
   }
 }
 
+void DownloadsDOMHandler::HandleUndoRemove(const base::ListValue* args) {
+  if (removed_ids_.empty())
+    return;
+
+  uint32 last_removed = removed_ids_.back();
+  removed_ids_.pop_back();
+
+  content::DownloadItem* item = GetDownloadById(last_removed);
+  if (item)
+    item->UndoRemove();
+}
+
 // DownloadsDOMHandler, private: ----------------------------------------------
 
 void DownloadsDOMHandler::ScheduleSendCurrentDownloads() {
@@ -563,9 +593,23 @@ bool DownloadsDOMHandler::IsDeletingHistoryAllowed() {
 
 content::DownloadItem* DownloadsDOMHandler::GetDownloadByValue(
     const base::ListValue* args) {
-  int download_id = -1;
-  if (!ExtractIntegerValue(args, &download_id))
+  std::string download_id;
+  if (!args->GetString(0, &download_id)) {
+    NOTREACHED();
+    return NULL;
+  }
+
+  uint64 id;
+  if (!base::StringToUint64(download_id, &id)) {
+    NOTREACHED();
     return NULL;
+  }
+
+  return GetDownloadById(id);
+}
+
+content::DownloadItem* DownloadsDOMHandler::GetDownloadById(
+    uint32 download_id) {
   content::DownloadItem* item = NULL;
   if (main_notifier_.GetManager())
     item = main_notifier_.GetManager()->GetDownload(download_id);