Show download interrupt reason in a tooltip

chrome/browser/download/download_item_model.h

 // Copyright (c) 2012 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_DOWNLOAD_ITEM_MODEL_H_
 #define CHROME_BROWSER_DOWNLOAD_DOWNLOAD_ITEM_MODEL_H_
 #pragma once
 
 #include <string>
 
@@ skipping 14 matching lines @@
 // This class is an abstraction for common UI tasks associated with a download.
 class BaseDownloadItemModel {
  public:
   explicit BaseDownloadItemModel(content::DownloadItem* download)
       : download_(download) { }
   virtual ~BaseDownloadItemModel() { }
 
   // Cancel the task corresponding to the item.
   virtual void CancelTask() = 0;
 
-  // Get the status text to display.
+  // Returns a short one-line status string for the download.
   virtual string16 GetStatusText() = 0;
 
+  // Returns a string suitable for use as a tooltip. For a regular download, the
+  // tooltip is the filename. For an interrupted download, the string states the
+  // filename and a short description of the reason for interruption. For
+  // example:
+  //    Report.pdf
+  //    Network disconnected
+  // |font| and |max_width| are used to elide the filename and/or interrupt
+  // reason as necessary to keep the width of the tooltip text under
+  // |max_width|. The tooltip will be at most 2 lines.
+  virtual string16 GetTooltipText(const gfx::Font& font,
+                                  int max_width) const = 0;
+
   // Rough percent complete. Returns -1 if the progress is unknown.
   virtual int PercentComplete() const = 0;
 
   // Get the warning text to display for a dangerous download. The |base_width|
   // is the maximum width of an embedded filename (if there is one). The metrics
   // for the filename will be based on |font|. Should only be called if
   // IsDangerous() is true.
   virtual string16 GetWarningText(const gfx::Font& font, int base_width) = 0;
 
   // Get the caption text for a button for confirming a dangerous download
@@ skipping 20 matching lines @@
 
 // Concrete implementation of BaseDownloadItemModel.
 class DownloadItemModel : public BaseDownloadItemModel {
  public:
   explicit DownloadItemModel(content::DownloadItem* download);
   virtual ~DownloadItemModel() { }
 
   // BaseDownloadItemModel
   virtual void CancelTask() OVERRIDE;
   virtual string16 GetStatusText() OVERRIDE;
+  virtual string16 GetTooltipText(const gfx::Font& font,
+                                  int max_width) const OVERRIDE;
   virtual int PercentComplete() const OVERRIDE;
   virtual string16 GetWarningText(const gfx::Font& font,
                                   int base_width) OVERRIDE;
   virtual string16 GetWarningConfirmButtonText() OVERRIDE;
   virtual bool IsMalicious() OVERRIDE;
   virtual bool IsDangerous() OVERRIDE;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(DownloadItemModel);
 };
 
 #endif  // CHROME_BROWSER_DOWNLOAD_DOWNLOAD_ITEM_MODEL_H_