Fixed chrome://net-export save dialog code

chrome/browser/ui/webui/net_export_ui.cc

 // Copyright (c) 2013 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/ui/webui/net_export_ui.h"
 
 #include <memory>
 #include <string>
 
 #include "base/bind.h"
@@ skipping 58 matching lines @@
   // Messages.
   void OnGetExportNetLogInfo(const base::ListValue* list);
   void OnStartNetLog(const base::ListValue* list);
   void OnStopNetLog(const base::ListValue* list);
   void OnSendNetLog(const base::ListValue* list);
 
   // ui::SelectFileDialog::Listener:
   void FileSelected(const base::FilePath& path,
                     int index,
                     void* params) override;
+  void FileSelectionCanceled(void* params) override;
 
  private:
   // Calls NetLogFileWriter's ProcessCommand with DO_START and DO_STOP commands.
   static void ProcessNetLogCommand(
       base::WeakPtr<NetExportMessageHandler> net_export_message_handler,
       net_log::NetLogFileWriter* net_log_file_writer,
       net_log::NetLogFileWriter::Command command);
 
   // Returns the path to the file which has NetLog data.
   static base::FilePath GetNetLogFileName(
@@ skipping 215 matching lines @@
 
 void NetExportMessageHandler::OnExportNetLogInfoChanged(base::Value* arg) {
   std::unique_ptr<base::Value> value(arg);
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   web_ui()->CallJavascriptFunctionUnsafe(net_log::kOnExportNetLogInfoChanged,
                                          *arg);
 }
 
 void NetExportMessageHandler::ShowSelectFileDialog(
     const base::FilePath& default_path) {
-  DCHECK(!select_file_dialog_);
+  // User may have clicked more than once before the save dialog appears.
+  // This prevents creating more than one save dialog.
+  if (select_file_dialog_)
+    return;
 
-  WebContents* webcontents = nullptr;
+  WebContents* webcontents = web_ui()->GetWebContents();
 
   select_file_dialog_ = ui::SelectFileDialog::Create(
       this, new ChromeSelectFilePolicy(webcontents));
   ui::SelectFileDialog::FileTypeInfo file_type_info;
   file_type_info.extensions = {{FILE_PATH_LITERAL("json")}};
-  gfx::NativeWindow owning_window =
-      webcontents ? platform_util::GetTopLevel(webcontents->GetNativeView())
-                  : nullptr;
-
+  gfx::NativeWindow owning_window = webcontents->GetTopLevelNativeWindow();
   select_file_dialog_->SelectFile(
       ui::SelectFileDialog::SELECT_SAVEAS_FILE, base::string16(), default_path,
       &file_type_info, 0, base::FilePath::StringType(), owning_window, nullptr);
 }
 
 void NetExportMessageHandler::FileSelected(const base::FilePath& path,
                                            int index,
                                            void* params) {
+  DCHECK(select_file_dialog_);
+  select_file_dialog_ = nullptr;
+
   BrowserThread::PostTaskAndReply(
       BrowserThread::FILE_USER_BLOCKING, FROM_HERE,
       base::Bind(&net_log::NetLogFileWriter::SetUpNetExportLogPath,
                  base::Unretained(net_log_file_writer_), path),
       // NetExportMessageHandler is tied to the lifetime of the tab
       // so it cannot be assured that it will be valid when this
       // StartNetLog is called. Instead of using base::Unretained a
       // weak pointer is used to adjust for this.
       base::Bind(&NetExportMessageHandler::StartNetLog,
                  weak_ptr_factory_.GetWeakPtr()));
 }
 
+void NetExportMessageHandler::FileSelectionCanceled(void* params) {
+  DCHECK(select_file_dialog_);
+  select_file_dialog_ = nullptr;
+}
+
 }  // namespace
 
 NetExportUI::NetExportUI(content::WebUI* web_ui) : WebUIController(web_ui) {
   web_ui->AddMessageHandler(new NetExportMessageHandler());
 
   // Set up the chrome://net-export/ source.
   Profile* profile = Profile::FromWebUI(web_ui);
   content::WebUIDataSource::Add(profile, CreateNetExportHTMLSource());
 }