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..f5638e880ac7c9377a068e46d8c5e68c100b1fa4 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());
@@ -230,7 +231,7 @@ base::DictionaryValue* CreateDownloadItemValue(
       break;
 
     case content::DownloadItem::MAX_DOWNLOAD_STATE:
-      NOTREACHED() << "state undefined";
+      NOTREACHED();
   }
 
   return file_value;
@@ -249,6 +250,7 @@ bool IsDownloadDisplayable(const content::DownloadItem& item) {
 DownloadsDOMHandler::DownloadsDOMHandler(content::DownloadManager* dlm)
     : main_notifier_(dlm, this),
       update_scheduled_(false),
+      last_removed_id_(content::DownloadItem::kInvalidId),
       weak_ptr_factory_(this) {
   // Create our fileicon data source.
   Profile* profile = Profile::FromBrowserContext(dlm->GetBrowserContext());
@@ -262,6 +264,7 @@ DownloadsDOMHandler::DownloadsDOMHandler(content::DownloadManager* dlm)
 }
 
 DownloadsDOMHandler::~DownloadsDOMHandler() {
+  FinalizeRemoval();
 }
 
 // DownloadsDOMHandler, public: -----------------------------------------------
@@ -310,6 +313,9 @@ 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(
@@ -438,8 +444,11 @@ void DownloadsDOMHandler::HandleRemove(const base::ListValue* args) {
 
   CountDownloadsDOMEvents(DOWNLOADS_DOM_EVENT_REMOVE);
   content::DownloadItem* file = GetDownloadByValue(args);
-  if (file)
+  if (file) {
+    FinalizeRemoval();
+    last_removed_id_ = file->GetId();
     file->Remove();
+  }
 }
 
 void DownloadsDOMHandler::HandleCancel(const base::ListValue* args) {
@@ -480,6 +489,18 @@ void DownloadsDOMHandler::HandleOpenDownloadsFolder(
   }
 }
 
+void DownloadsDOMHandler::HandleUndoRemove(const base::ListValue* args) {
+  if (last_removed_id_ == content::DownloadItem::kInvalidId)
+    return;
+
+  if (main_notifier_.GetManager())
+    main_notifier_.GetManager()->ReviveDownload(last_removed_id_);
+  if (original_notifier_ && original_notifier_->GetManager())
+    original_notifier_->GetManager()->ReviveDownload(last_removed_id_);
+
+  last_removed_id_ = content::DownloadItem::kInvalidId;
+}
+
 // DownloadsDOMHandler, private: ----------------------------------------------
 
 void DownloadsDOMHandler::ScheduleSendCurrentDownloads() {
@@ -561,16 +582,37 @@ bool DownloadsDOMHandler::IsDeletingHistoryAllowed() {
               GetPrefs()->GetBoolean(prefs::kAllowDeletingBrowserHistory));
 }
 
+void DownloadsDOMHandler::FinalizeRemoval() {
+  if (last_removed_id_ == content::DownloadItem::kInvalidId)
+    return;
+
+  if (main_notifier_.GetManager())
+    main_notifier_.GetManager()->FinalizeRemoval(last_removed_id_);
+  if (original_notifier_ && original_notifier_->GetManager())
+    original_notifier_->GetManager()->FinalizeRemoval(last_removed_id_);
+
+  last_removed_id_ = content::DownloadItem::kInvalidId;
+}
+
 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;
+  }
+
   content::DownloadItem* item = NULL;
   if (main_notifier_.GetManager())
-    item = main_notifier_.GetManager()->GetDownload(download_id);
+    item = main_notifier_.GetManager()->GetDownload(id);
   if (!item && original_notifier_.get() && original_notifier_->GetManager())
-    item = original_notifier_->GetManager()->GetDownload(download_id);
+    item = original_notifier_->GetManager()->GetDownload(id);
   return item;
 }