[Download Notification] Show preview if downloaded file is image

chrome/browser/download/notification/download_notification_item.h

 // Copyright 2015 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.
 
 #ifndef CHROME_BROWSER_DOWNLOAD_NOTIFICATION_DOWNLOAD_NOTIFICATION_ITEM_H_
 #define CHROME_BROWSER_DOWNLOAD_NOTIFICATION_DOWNLOAD_NOTIFICATION_ITEM_H_
 
 #include "base/strings/string_number_conversions.h"
 #include "chrome/browser/download/download_commands.h"
 #include "chrome/browser/download/notification/download_notification.h"
+#include "chrome/browser/image_decoder.h"
 #include "chrome/browser/notifications/notification.h"
 #include "chrome/browser/notifications/notification_delegate.h"
 #include "chrome/browser/notifications/notification_test_util.h"
 #include "content/public/browser/download_item.h"
 #include "grit/theme_resources.h"
+#include "third_party/skia/include/core/SkBitmap.h"
 #include "ui/message_center/message_center.h"
 #include "ui/message_center/message_center_observer.h"
 
 namespace test {
 class DownloadNotificationItemTest;
 }
 
-class DownloadNotificationItem : public DownloadNotification {
+class DownloadNotificationItem : public DownloadNotification,
+                                 public ImageDecoder::ImageRequest {
  public:
   DownloadNotificationItem(content::DownloadItem* item,
                            DownloadNotificationManagerForProfile* manager);
 
   ~DownloadNotificationItem() override;
 
   // Methods called from NotificationWatcher.
   void OnDownloadUpdated(content::DownloadItem* item) override;
   void OnDownloadRemoved(content::DownloadItem* item) override;
   void OnNotificationClose() override;
   void OnNotificationClick() override;
   void OnNotificationButtonClick(int button_index) override;
   std::string GetNotificationId() const override;
 
  private:
   friend class test::DownloadNotificationItemTest;
 
+  enum ImageDecodeStatus { NOT_STARTED, IN_PROGRESS, DONE, FAILED, NOT_IMAGE };
+
   enum NotificationUpdateType {
     ADD,
     UPDATE,
     UPDATE_AND_POPUP
   };
 
   void CloseNotificationByUser();
   void CloseNotificationByNonUser();
   void Update();
   void UpdateNotificationData(NotificationUpdateType type);
-  void SetNotificationImage(int resource_id);
+
+  // Set icon of the notification.
+  void SetNotificationIcon(int resource_id);
+
+  // Set preview image of the notification. Must be called on IO thread.
+  void OnImageLoaded(const std::string& image_data);
+
+  // ImageDecoder::ImageRequest overrides:
+  void OnImageDecoded(const SkBitmap& decoded_image) override;
+  void OnDecodeImageFailed() override;
 
   // Returns a short one-line status string for the download.
   base::string16 GetTitle() const;
 
   // Returns a short one-line status string for a download command.
   base::string16 GetCommandLabel(DownloadCommands::Command command) const;
 
   // Get the warning test to notify a dangerous download. Should only be called
   // if IsDangerous() is true.
   base::string16 GetWarningText() const;
@@ skipping 10 matching lines @@
   // Current vilibility status of the notification.
   bool visible_ = false;
 
   int image_resource_id_ = 0;
   content::DownloadItem::DownloadState previous_download_state_ =
       content::DownloadItem::MAX_DOWNLOAD_STATE;  // As uninitialized state
   scoped_ptr<Notification> notification_;
   content::DownloadItem* item_;
   scoped_ptr<std::vector<DownloadCommands::Command>> button_actions_;
 
+  // Status of the preview image decode.
+  ImageDecodeStatus image_decode_status_ = NOT_STARTED;
+
+  base::WeakPtrFactory<DownloadNotificationItem> weak_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(DownloadNotificationItem);
 };
 
 #endif  // CHROME_BROWSER_DOWNLOAD_NOTIFICATION_DOWNLOAD_NOTIFICATION_ITEM_H_