[Download Notification] Clean Up: Initialize properties in header file

This patch is just a cleanup. No functionality is changed.

BUG=none
TEST=none

Review URL: https://codereview.chromium.org/1129023005

Cr-Commit-Position: refs/heads/master@{#329822}

chrome/browser/download/notification/download_notification_item.cc

@@ -74,10 +74,7 @@ std::string DownloadNotificationItem::NotificationWatcher::id() const {
 DownloadNotificationItem::DownloadNotificationItem(content::DownloadItem* item,
                                                    Profile* profile,
                                                    Delegate* delegate)
-    : openable_(false),
-      downloading_(false),
-      image_resource_id_(0),
-      profile_(profile),
+    : profile_(profile),
       watcher_(new NotificationWatcher(this)),
       item_(item),
       delegate_(delegate) {

chrome/browser/download/notification/download_notification_item.h

@@ -103,17 +103,14 @@ class DownloadNotificationItem : public content::DownloadItem::Observer {
 
   scoped_ptr<std::vector<DownloadCommands::Command>> GetPossibleActions() const;
 
-  bool openable_;
-  bool downloading_;
-  int image_resource_id_;
+  bool openable_ = false;
+  bool downloading_ = false;
+  int image_resource_id_ = 0;
   Profile* profile_;
   scoped_refptr<NotificationWatcher> watcher_;
-
   scoped_ptr<Notification> notification_;
-
   content::DownloadItem* item_;
   scoped_ptr<std::vector<DownloadCommands::Command>> button_actions_;
-
   Delegate* const delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadNotificationItem);